We Test 5 Jeep Cylinder Heads [How Much is Porting Worth?]
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- เผยแพร่เมื่อ 22 ส.ค. 2024
- We're back with Newcomer Racing (www.newcomerrac...)as they slam FIVE different Jeep cylinder heads across the dyno to see what works best. We've got a wide variety, from stock ports, to a fully hand-ported Edelbrock Performer cylinder head. This is the second of a two-part dyno testing series. Check out the first video where we looked at whether roller rockers help make power here: • Do Roller Rockers Make...
Also, you can check out our complete build of Newcomer Racing's budget stroker Jeep engine here: • Big Power Jeep Straigh...
years ago I had a 4.0 mated to a 5 speed with grand ma first and a NP 205 transfer-case in a J 10. it was one of the most capable jeeps I ever owned and would still be in my garage except for the dread of all jeep owners it was built from a cheaper steel as american motors was nearing the end of it's life and was sold in Connecticut. needless to say when I got it it was a rust bucket but it had a very low mile 4.0 and the 5 speed I swapped in the 205 because I had a chance to get one and it was the best mod and the only one I did to the truck. I got 8 years out of it before it rusted back to the earth but the motor, trans and transfer-case went in to my little brothers 67 J 10 and still powers it to day that was over 20 years ago now and it's still his daily driver.
These 4.0 builds have been really fun. Thanks guys.
Great video. Some very impressive numbers. That torque is awesome. Exactly what u need in a trail rig, low revving 4.0 or in this case 4.5. People that bounce these engines off the limiter rode the short bus as kids.
Exactly! You can't compare this to an LS or a Coyote. These engines have a different purpose. Thanks for watching!
why are you scared of rev limiter?
@@Tanner731 because he has a brain 🧠
This video really puts the emphasis on choice for application. I’d imagine the heads on a forced induction build would show highly different graphs on the dyno. It really shows how, too much porting, that’s specifically designed for forced induction. Put on naturally aspirated builds. Can rob power. And the beauty of this video is. It gives the layman a better understanding of gas flow and velocities. Thus helping people chose the right parts for their application.
Your spot on when you say that the stock heads, with a descent valve seat job. Are the best for a budget upgrade on most applications. Where as the standard and ported
Edelbrock variants are much better suited for stroker and forced induction builds.
Again a cracking comprehensive, and in-depth test coverage of a subject that is highly relevant for lots of people wanting to update, and modify their straight 6 motors!
Best part of this channel is the 4.0 builds.
Please more videos covering these jeep stroker motors!
I didn't even know there *were* 5 different cylinder heads 🥳
I about fainted. I read "5 cylinder" and thought this was one of those conversions.
lol
Basically 2 heads, 1 factory with 4 variations and the Eddy lol
shaadydog1 - Yeah, I figured that out once I actually watched the video, lol
renix, early mopar, 2nd gen mopar and infamous 0331, with some revisions inbetween
Thanks for the pull information. The crank harmonics are definitely an rpm limiting factor here. That being said, it seems all the business occurs well before 5k as it relates to torque. I mention this as it appears a mildly ported 7120 casting would have spanked the Edelbrock head on this block configuration. Other than the weight reduction and possibly lower emissions due to the chamber, the Edelbrock is a waste of money to anyone with a 7120 casting to start with. What is not illustrated is how well the stock castings flow at low valve lift.
That's a whole lotta money for 15 horsepower!
This is one of those mods you can do yourself for free with just a dremel. When ever I have to a head job I usually trim up the ports. I use a gasket to mark them, and the manifolds and match. Its not as good as machined, but never had any ill effects. Always noticed a slight increase. 15hp/tq ain't much but every little bit adds up to big gains.
yep simple porting and polishing works wonders with a nice cam and way cheaper too then all the different head dancing hoopla
@@ChannelZeroOne The heads in this video had WAY! more work than gasket matching with a dremel. Big valves, bowl work, port reconfiguration, raised roof, etc... There was nothing free about it! And If that's what it took to see a 15 horsepower gain, a little dremel work wouldn't even show up on the dyno.
@@1996slamster You forget this ain't a stock to stock comparison anyways. I always get haters, but they are always slightly faster than stock. I always assume the gains are minimal, but enough to notice. I dont just decide I am gonna dremel out my heads. This is something I do when I need to replace a head or something. Making a headache worth it. Every little tweak adds up over time.
Channel Zero One Haters?! Since when were we talking about a set of heads you’ve worked on, we’re talking about the heads in the video, and none of the heads in the video were simply gasket matched with a dremel. They had huge amounts of work done to them requiring expensive machine work, hand porting and flow bench time all equating to $$$
For my application, the stock Edelbrock head is the one. Thanks for the dyno runs on all of those heads. A lot of great info.
Thanks for watching!
I agree. Think I'm going to purchase one when I rebuild my stock HO and drop in a RV cam. The weight reduction will surely help make this a peppy street engine.
For my money, n/a, the ported tupy head seamed to be the best bang for the buck. But for a proper mountain rig a turbo would be a huge boon at altitude.
This was a surprising test. I was expecting alot more from that Edelbrock.. both stock and modified.
probably at the limit of the intake manifold. those ported edelbrocks look like they should move a ton of air.
@@deltaphisig also being aluminum it can take more timing without detonation. Without messing with the tune, it’s going to be difficult to get the most out of it
I spent 20+ hrs porting and polishing the 0630 for my 4.6L/280cu in. I used the Mopar P5249464 springs(good for lifts up to .525”) and the NLA P4529230ab cam (.45” lift). Awesome Testing!
Thanks! And thanks for watching!
With todays tech, I'm a bit surprised there hasn't been a billet cross flow head for the 4.0L.
EDELBROCK = make a alloy performance head !
Great video! Would love to see a test of the different intake manifolds that were offered!
I have an ultra-low mile 92' Sahara (think Jurassic Park Jeep) and am considering a supercharger.
Wow, what a test! I LOVE the no B.S.
You earned another subscriber for this!
Awesome. Thanks for watching!
Any heads with similar bore spacing that could be adapted? BMW, Toyota, Nissan, Jaguar... create something like the old Pontiac SOHC. Also I know it’s time and expense but some of the ported heads would probably have liked a different cam to bump up the torque. If the exhaust picked up significantly the need for less duration/overlap would help that. Even as it stands though nice gains and great content.
did you guys play around with ignition timing on the edelbrocks to see if the chamber shape liked anything different then the iron versions?
I'm quite surprised the ported TUPY 0331 did so well. I would have figured the restricted exhaust floors would be a major restriction.
Man I loved watching that 4.0L making V8 power....
6=8 😁
more like a VERY mild v8 with a small cam power.
@@3rdGenGuy totally agree super stock smaller v8 power.
LOL @ comparing 6cyl dyno HP and V8 WHP... The turbo will be the nice, would also like to see a Cobra 112/122 retrofitted.
with way better fuel economy
super cool comparison as always. One of my favorite channels for all that is horsepower.
Awesome, thanks for the kinds words!
The last Ironhead, looks like it would probably have produced somewhere close to about 330 or better horsepower if it didn't have the larger combustion Chambers to allow for forced air you can. Maybe a slightly domed piston would have worked. That might bring you up into that 330 to 350 horsepower range. But that would have been really ideal and I don't think you had quite enough to him for that horsepower. Looks like the best head for the money was the stock Edelbrock. Just a little bit of cleaning of the ports, which most people can't do. Helps and not opening up the exhaust ports greatly would help in reduction of reversion. Which could cause issues down the road with the coking up the intake.
Built a 4.6 with a tupy head that has been really noisy on startup and a little bit piston slappy but I can't blow it up tried a few times... has a 229 cam 4.2 rods and pottenger dished 26cc Pistons, even with the dish it likes 89 doesn't like 87 at all after swapping the 229 cam..
Got rid of the 0w40 and dumped in some 5w30 and a little Lucas zinc additive and it's way quieter now, maybe it just likes the thinner stuff still has plenty of oil pressure
But does it run well? Sounds like a fun ride!
Dodd Garger i went with the 4.2 rods, h802cp30 pistons(15.x cc), 230 cam, and put it in my lowered 2wd 2dr XJ with ax15 and LSD. I’d usually be in top 1/3 at autocrosses. Wish yt would let us post pics. I’m gonna redo it with +.090”diamond pistons and the eagle 6.150s long rods i’ve been hoarding for years.
@@grad0n Very sweet. Always thought of autocrossing a 2door 2wd. I have a 2 door 4wd daily stocker that I thought maybe???
@@99jeepxjguy97 i have a 99 2-dr 4wd 5-sp that I’ll be autocrossing this season. I just put an eaton truetrac in the back and will swap the 231 out for the 242 with fulltime option.
Can't wait to build might. I can't see spending the money on the aluminum head though vs just getting my tupy head ported.
Head porting may end up costing as much as the aluminum head...
I would have liked to have seen mention of testing timing and fuel tuning with each head. Different ports, combustion chamber shape and compression ratio are such significant changes that tuning fuel and timing could, maybe, completely change those results.
Suggestion. Make the torque lines and horse power lines for each component the same color in future videos.
As in:
Tupy Blue/Blue
Edbk: red/red
It will make it far easier to read. and it gives you the ability to use more contrasting colors for each component as you have 1/2 as many colors to come up with.
Mines a 2000 wj. Came with the
when you run a side mounted four barrel carb the primaries face the intake valves, how about testing the four bangers (2.5), the throttle barrel injection manifold is way too small, but the electronic (four injectors) has a better runner design, the throttle body , will bolt on and you plug the four injector ports, the four banger jeep also had a twin cam cross low head
Like screaming into the void. Trying to make power out of non crossflow heads.
But that's what makes it heat fun. Trying to achieve the impossible 😁
True.
But there were many european, small non-x-flow n/a engines tuned to aprox 100hp per 1Liter of displacement.
The benefits aren't worth the drawbacks.
@@KC9UDX agreed. Unless class rules demand it.
@@KC9UDX what benefits?
@@jareknowak8712 beats me. But I sure know about the drawbacks. Maybe I'll make a video!
3500 rpm.....like to know what happens at the lower rpms.Where we use the motor the most.
A custom crossflow head is what this engine needs, that should help get the air in and out faster.
I wonder if you could drop a more modern I6 into these older jeeps to take advantage of crossflow heads etc. The Ford Barra might be a good choice, similar 4L capacity and undersquare design but with the modern bells and whistles like DOHC and 4 valves per cylinder, VVT, etc.
@@nerd1000ifyinteresting idea, considering 4.6 Ford SOHC valvetrain parts fit the 4.7 PowerTech SOHC
Same bore spacing as the small Ford V-8s. The SBC/LS is only .020" more. The Ford and LS would need new bump sticks due to valve position. Not sure on the SBC. for DOHC the Nissan Infinity V-8 is about .030 on bore spread. The GM LQ-1 is the same as the LS.
Have you done any jeep 3.7 engines? I know that may sound silly but watching this is like myth busters
needs a bigger cam on that edelbrock ported head, try a 234 or 240* with higher compression. imagine it as a v12 but this is one bank.
Please understand that most of us jeep 4.0 owners are looking for off-idle torque increases rather than high rpm HP. Please consider asking “Newcomer racing” to consider building a high torque off idle engine that will perform off road. I am bringing my 04 rubicon to them as soon as my relocation from the Great North Woods of Maine to SC is complete.
Here, here.
these guys know shit about the 4.0 culture, torque man, not rpms...
We hear you and we build from mild to wild and everything in between. Don't think just because these engines can rev to 6,000rpm's that they have no bottom end torque, quite the contrary. You can't control the load on a dyno at low rpm's very well for those who do not understand.
@@keithnewcomer4406 Thank you for your reply. I look forward to having you rebuild my 2004 I-6
@@keithnewcomer4406
I've got a 2004 WJ. Is it possible to build a stroker 4.0L based engine for a little more hp/tq and still be California smog legal?
I get 18 mpg @ 70 mph. Can I keep the mpg high?
Am I asking too much of this engine design? Thanks.
Thanks very much....Guy's it's always fun to watch your video's...!!!
Thank you! And thanks for watching!
As a jeep enthusiast, let's be honest , the straight 6 is awesome for what it does not matter if it's carbed, a renix , or OBD2 . But making big power is not it's niche.
Awesome work fella's. Great video 👍
Thanks, and thanks for watching!
This is so great im building 2 4.0s for my jeep rn
I love this series
Thank you!
I had a 0331 head that I ported and then threw a turbo on it and drifted that jeep for almost 3months until it made a window in the block
what about the ProMaxx head ?? have you ever been able to test one of those? And what stock jeep head does the ProMaxx compare to? the 0331 or 0630 ?
I would love to see the last one with about 15 pounds of boost !!!!
That's a big turbo!
@@KC9UDX Not overly big, an HX-35 might be just right.
Put that engine in an old Rambler American and hunt modern muscle cars......lol
@@KC9UDX One of the things the Youngsters forget, it's all about Power to Weight Ratios.
Starting with a 2000 pound old car is far better than starting with a 4000 pound car.
Some modern things I like: modern programmable ignitions systems, Electronic Boost Controllers both make power and my engines survive. But I also like Carbs, I can make them do what I want.
I'm old and don't like to follow the heard to closely. So I use what modern parts give me an advantage and leave the rest behind. The engine on my test stand right now is a Ford 300 six, a boat anchor, but with the cut, modified, and welded Chevy LS3 head I made for it it might raise a few eye brows. I'm still working on a proper intake for it and it will see boost. The most expensive part so far has been the semi-custom Molnar rods but it's insurance.
I'm rambling,
Good Hunting
@@johnparrish9215 I've got to apologise, John. Your comment came in my notifications looking like a reply to my comment about cross-flow vs. not cross-flow heads. So my reply to you was totally out of context. I don't disagree with you at all.
@@johnparrish9215 by the way, I've always liked turbochargers. I yoosta have ideas about putting one on a 258 or 242. But I've become addicted to high compression. 😁
For the non-racer, just-meaty jeep configuration, it's the "Ported TUPY" vs. The Stock Edelbrock. What's the ballpark cost for the ported TUPY setup vs the stock Edelbrock (around $1800)? Do you guys do that? My '03 has the TUPY and it's time to clean it up!
if you go with a maximum valve size, does the spark plug need to be shorter to not interfere with the travel of the valves?
That engine started handicapped from scratch. Same for all USA domestic I-6's.
OHV, NON-CROSSFLOW cast iron head.
Cumbersome BOTH intake & exhaust manifolds. Even Air/Fuel distribution be damned.
Meant for basically trucking duty (Under square design most of them not lending itself to revving freely, overbuilt and heavy rotating assemblies).
I would be happy with the Edelbrock Aluminium head just for all the weight saved, any additional PERFORMANCE is just a nice bonus but not at that price, HELL NO.
Or go the easy route and LSx everything or install a turbo'd FORD BARRA.
Then don't buy one. And please don't block the trail, this is not F1 racing.
I have been considering an aluminum head for my build. How much would it cost to port the tupy head. The aluminum head is pricy as is. I want to weigh the cost to gains.
I would choose that turbo head anyday. :-)
Y'all sure make installing the manifolds look easy.
That's because they are.
@@ChannelZeroOne uh-huh... When's the last time *you* put one of these together? 😉
@@KC9UDX 6 months ago.
@@ChannelZeroOne which intake and exhaust? The stock ones aren't that difficult, provided you don't care to get an accurate torque reading on every screw.
@@KC9UDX If you need a torque wrench for intake and exhaust bolts you are a rookie. Head and bearing bolts yes, the rest no. There are 2 guide slots you start with those up first. The bolts by the firewall are always a pain no matter the vehicle.
I’m having to replace my 4.2 .30 over bored block 4.0 head conversion with a 4.0 due to a cracked head stud boss.
I was thinking of swapping over the 4.2 crank and boring the 4.0 to fit my pistons. I’ve heard that the 4.0 con rods (in this combo) would be a better overall displacement. What’s your take on this?
does the aluminum head run cooler? If so would it be enough to pull a little more timing to make even more?
With all that different chambers volume,did you play with ignition timing ?
Remember boosted leave rough na smooth for atomization why not have pricing also seems like edlebrock head out of the box is the best bang and if you touch it up it’s better then all
Pricing can change so fast any number I have can be out of date pretty quick. If anyone is serious about purchasing an engine, I always leave links to the engine builder. Thanks for watching
Not enough compression to accurately test the aluminum heads. You need a min of. 9.4:1 because of the thermal efficiency of aluminum. I'm running 9.7:1 on 87 Oct pump gas due to dynamic compression loss from thermal efficiency. It would be great if you guys could test those 2 heads again with a real build.
Dynamic pulls that start at 3500 leave a lot on the table in my opinion. We need the torque numbers from off idle to 4500 where most of us Jeep guys live. And..what does it cost to do up a TUPY like the one here?
Hand porting cylinder heads is becoming a lost art.
Not really, all CNC ported heads get their pattern off of a hand ported head. The CNC just makes it cheaper to reproduce.
Haa. Yea right. Louisiana.. all over the place.
That edlbrock is way better then any of the other options + it is 37 pounds lighter it’s a no brianer I would like to see what it does with stock cam
Cool builds, it’s painful to watch them drag those precisely machined surfaces around on that bare metal workbench tho
What timing degree numbers were you guys running with the tests? I would like to see a video about 4.0 stock and striker tuning. And I am sure that many other jeep guys would also. So how about it? Maybe even some carburetor and EFI.
Watched this about a year ago and been looking for it again since I now have a jeep 4.0. Lol. Only problem is I would like “street” power not full redline power.
Biggest restriction is at the carburator prop pick up some more pony's if you could free up that air flow
put a turbo = a matched one not too big = i bet you can see over 500hp easy .
This is awesome!
Thanks!
I was thinking of a Slant Six for my build of a t bucket but maybe this is better?
@Clayton Pope
What VW diesel did he run?
An 80s idi style or a later TDI?
The TDI in the 3rd gen can be made mechanical injection used from the idi fairly easy.
Then you get modern power with old style reliability.
I built one years ago, basically stock except a little more boost and it ran tractionless 14 flats in a old rabbit.
Chevy 292, ford 300 ... bigger.
I have a set of those rockers, but haven't been able to find any reference on how to set them. Any preload required, gap, etc... How do *you set them?
You didn't discuss anything about combustion Chambers how many CC's in the combustion Chambers and what is your compression ratio of each??
Go keith!! Miss you 💛
MOST INTERESTING
THEY'RE A HSRD MOTOR TO BEAT FOR RELIABILITY AND THANX AGAIN MOST INTERESTING I DO SAY
need advice on swapping cam in my 05 jeep wrangler? i am having trouble getting an aftermarket keyway style cam ! can i use a earlier pin style cam, timing gear set and cam button bolt and eliminate the cam thursh plate? any help please! terry.
Someone needs or needed to make a crossflow head for the jeep. The OEM head design is right out of the 1920s.
Yeah, but it served well for 80 years ...
Wonder why they came up with a 100 deg lca cam if it's only running to under 6000 rpm ?
This is cool and all for people with Jeeps pre 2000. But what about people with "newer" TJ that have to deal with OBD2 and the like to keep it road legal? Anyone making an ECU/TCU programmable computer?
post 2000 4.0s are only good for parts...
@@omegarugal9283 Unless that's what you have as a DD. I would like it if someone would makeone. I have no clue how to go about it. But they make them for every V-8.
Not a problem, 96-06 are the best years due to being able to tune the factory ECM. Completely "Road legal"
@@keithnewcomer4406 This may be the most useful info here. As a thank you, I will mention "Metric Mechanic", I have no idea if they are still around, the point is that they did allot of flow bench work ('80's BMW) and well, the idea about "smooth ports and runners" ... take 40 grit sand paper and a mirror both mounted on the same board so that the tilt angle is same. One drop of water one each, tilt and observe. The flow bench testing proved it out, Merc Benz even had a patent out on cutting ridges onto the outside of the valves.
There was a America's Cup boat that was also using this "rough" to go faster.
Hope this is useful, 40 year old tech, if you can find the old Metric Mechanic Missouri stuff, give it a read.
Only disappointing thing in this video is there isn't an off the shelf head I can buy that will work as well as a ported factory head. I don't know anyone I trust to do porting right.
They will put all those modifications on it and yet put that restrictive spacer on that they need to shave the center cross out of The Middle of the spacer
What you suggest I do first for my 4.0 for more torque
Anybody know if ty head fits a 1991 block? Which gaskets will I need? Idk jeep stuff, never owned one till now
I xont know nothing bout 16 thousands .but sure sounds sweet
How much would you do a 7120 head like the orange one you ran?
I have a 1990 Limited Cherokee 4.0 with 153,000 original miles.
I was thinking about a new intake and throttle body & headers. Now I'm wondering if I should go ahead and port the original head, add new valves and springs as well? I'm more interested in fuel economy gains than I am horsepower or torque.
Should I just go with my original plan or dig a little deeper and do some work to the head itself?
Porting the head is going to help you burn more fuel. I don't think you will see any fuel economy gain. But for that matter, I don't think intake and exhaust changes will help either. Fuel economy is about combustion efficiency and parasitic drag. Maybe a cutting down the head to improve the compression ratio. Stuff like that.
@@TheHorsepowerMonster But how much cut to increase compression? Looking to still be able to run 87 daily and 89 for working (trailer, offroad, etc. . . ) .015" milled off?
Guys I need some help. Which head 603 or 7120 would you run on 4.2 bored 40 over. I just want to up some better performance in my yj street and light off-road work.
P.S. If treated right, that 6 cylinder engine will give you 300,000 miles of use. Mine had 246,000 plus when I sold it and it went another 60,000 miles before it got totalled in a wreck. As long as there isn't a maniac behind the wheel, they're good to go.
Mine got some flattened cam lobes at 50k miles... and I treated her like a dream. Not all of them go for 300k miles. :)
I have a big question, what serial number are the springs and what brand do they use for that camshaft?
They were Comp Cams LS springs and I think the cam was from Bullet Racing Cams. Thanks for watching
The Horsepower Monster LS comp cams will be those of 26995 part number
You have a lot of 4.0's out there that use an ECM. Who does tuning on them???
Flyin' Ryan at frptuning.com is pretty good
Did I see flat-top pistons in there?
What was the average compression ratio?
I think it's like 9.5:1
Love my 4.0s!!!!!
great video!
Thanks! And thanks for watching
Hey! I have a cracked head on my 2000 Xj from the usual casting issues I was just wondering if you guys know what the most cost effective replacement is and where I can purchase it? I want it to last forever although increased performance would be nice. Thanks!
I had the same issue and went with a new Promaxx solution that’s complete for $800
Hmmm what is best real world cam for near stock 630 head? Not the highly modded one in video. Say idle to 4200 rpm? I'm not going to ever see above that.
If you are never going to get above 4,200 rpm, that's totally cool. But it doesn't mean nobody else wants to.
I asked a simple question for daily driving and trails. Idle to say 3800-4000? Max torque at lower rpm. Okay if you all do not really know.
Do you guys sell that intake manifold and carburator?
Check with Keith at www.NewcomerRacing.com, and thanks for watching!
Damn 300 hp Jeep motor that’s stout
Where is the intake from?
Without testing the Hesco head this test is really incomplete
testing 5 different veas wuth a same camshaft ? no way !!!
I wanna see yall.build a Ford 300
All that work yet no one made a cross flow head ,.?,
What exhaust manifold(header) is that?
It is one Newcomer fabricated himself using stainless pipe.
Some flow numbers would have been nice.
Use an Aussie falcon motor and use these as boat anchors
Why not show everyone how to do that?
Victor it ain’t rocket science
Barra's are far more expensive and much harder to find parts for than this.
Did he just say they were all in there swapping head?
LS swap it is!
why doesnt someone have the sense to build a crossflow head like the tunnel port heads that ford used to make? The 4.0 head is a design out of the 1920s.
Edelbrock basically did the aluminum head with the same layout as the stock CI head for one reason. It's spelled CARB. They wanted an aluminum head that would be street legal in Cali. Plus ask yourself. Just what would the market be for an aluminum crossflow head for this engine. Would it pay for development and tooling? Granted 3D printing has made it a lot easier to produce experimental castings. But enough cheaper to justify the costs? If (the biggest word in the English language) money is no object there are options. Two Windsor, Cleveland, LS or SBC heads cut and splice together. Or two GM DOHC V-6 heads with the 4.400 bore center. Somebody was doing that for the Pontiac OHC 6. Or possibly a set of Infinity V-8 heads. They're pretty close too. The best way to really get really big power out of a 4.0 is forced induction. Barney Navarro got 600 to 800 horsepower out of a sleeved 199 in the sixties. They only blew the motor when they went to Willow springs for some testing. The dry sump was only set-up for turning right.
Remember when GM took a Cylcone pick-up out to the salt flats and made a big deal out of it? The next year one of the Jeep power train engineers took a Comanche out that he built on is own dime and shredded the records GM had spent big bucks to set.
Tupy all day
I am wondering that myself: what happens to average numbers if they start their pull at 2500 instead of 3500? The TUPY may be the better all purpose head - not everybody screams through the woods churning 5k on the tach.