It's funny you would pick a vacuum secondary carb and a single plane manifold. I've got a 450hp 293 that has over 400 ftlb of torque from 2800 to 5100 rpm. Guess what manifold is on it. Hotrod magazine did a dyno test on the rpm airgap and the jr. where the jr gave up so much down low with relatively the same numbers as the airgap. If you need a single plane, and I don't believe you do, get the Victor.... Also I use a 750 mechanical carb, I tried a 600 dp the 750 made 9hp more at 6300rpm and 2 to 3 every where else...
The VIctor Jr will be extensively modified to fit my specific combination and needs. An RPM air gap falls off above 6500, my engine will want to turn 1000-1500rpm more than that . Unfortunately the Super Victor doesn’t fit under the stock hood profile. As for the vacuum secondary carb, it’s a choice based on numerous factors, but as a street car and for use on a road course it offers the air and fuel control necessary for the power level and I have extensive experience with them for drivability purposes that make them more enjoyable to drive. A mechanical secondary would require more effort to tune, balancing the trade off between power and drivability. Your power difference was most likely entirely in fuel delivery and not an airflow difference, at that engine speed your displacement can only consume about 535cfm.
Thanks for the overview. My dad drove nothing but Ford, but I'm into mopars. I enjoy your channel. While listening to your explanations, I dont disagree, though I am curious about a couple things. Why would Ford/Shelby design an intake with two signifcantly different lengths of runner, when edelbrock solution seems pretty obvious. I know Eddy airgaps are a pretty good choice for any steerable performance engine. There had to be a reason for the shelby runner length choice.. Would it to have been to broaden the powerband of the engine? I'd think there is a good chance. You quoted the power difference at peak HP of 15 or so between the shelby and the rpm airgap. That may be so, but peak numbers are for bragging, area under the curve is for winning and driveability. It would be interesting to see the graphs of these power curves to compare. Love your videos
The intake on the Shelby GT350 was designed at a time when they didn’t understand why the manifold made more power, they just observed that it did. It’s actually a little bit confusing “who” designed the manifold, Edelbrock sold the same manifold as the F4-B but early Shelby castings were made by other manufacturers. The Shelby intake design was based on the same philosophy used on FE engines, which had low riser, medium riser, high riser, tunnel wedge, and tunnel port heads and intakes. While the ports on each head also changed, the manifold also changed, with the carburetor pads being raised incrementally in the thought that the air fuel mixture would have an improved “straighter” shot through the intake port at the valve. Both the RPM and RPM Air Gap will make more power everywhere, not just up top, throttle response is better, torque is better, horsepower is better. They distribute the air fuel mixture more effectively and their ports are more efficient and can move a larger quantity of the air fuel charge with less restriction. If you run both intakes on the same engine for the same test, both the average power and peak power will show the Shelby manifold is inferior, not just the peak numbers.
Also, you mentioned going with a traction loc diff. No Detroit locker? Too noisy or not in your car? Just curious. And if you still have your locker would you sell it?
My car was a 28-spline open differential like most GT350s in 1966. The Detroit Locker is fine for drag racing but noisy on the street. The Traction Lock is smooth and quiet and does well overall, but has some limitations. If I’m not happy with it in my various uses, I’ll probably install a Torsen T1 geared type differential. On a car like mine that is will be a serious driver, originality is not quite as important.
maybe trim the bread up to the top of the Black Sabbath letters on your shirt, lmao just poking fun. My 65 coupe , Feb of 65 is WIMBLETON White , I read after april 65 you couldn't get this Color because of Shelby , & the Gt-350's the coupe's white was a delete or changed ?. I did a flat tappet & it Burnt up, Now everything is Retro roller !! no break in is he Key!! I'm using a Edlebrook #2221 cam .520 lift & Dura. @ .050: 227°/234° ! very streetable.
Hydraulic roller is the way to go these days, I’ll be running one in my combination. What a lot of guys don’t realize is the hydraulic roller with equal specs to a mechanical or hydraulic flat tappet cam the hydraulic roller at higher lifts has significantly more duration, as much as 30-50° at .200” to .500”+ valve lift.
As for Wimbledon White, it was a staple color for Ford throughout the ‘60s and ‘70. Even when other whites were available during the period It was available. It was never considered a “Shelby exclusive” color.
It doesn’t really matter. You still have a pair of cylinders firing successively on the both banks. With 1-5-4-2-6-3-7-8 you have 4-2 and 7-8 With 1-3-7-2-6-5-4-8 you have 1-3 and 6-5 Overlay the firing order between a Chevrolet V8 and a Ford V8 and you’re in for a surprise, the only reason the firing orders are different is because of the cylinder numbering, but they actually fire in the same exact sequence. And Chevrolet’s firing order swap was no different from Ford’s. It’s truly a moot point for power production.
Fabulous video. I am building a fake gt350. I have a 289 .030 calculating maybe 10:1 with gt40p heads and 120lbs seat pressure..roller rockers with screw in plugs just because... Old school comp 280h flat hyd. Cam. I had an F4B but am ditching it for the upgraded blue thunder Cobra moniker intake. Also I'm running a 4.11 in the 8 inch with an auburn diff. Think I could expect 325+ horsepower? That's my goal. I know the p heads peter out at around those numbers. I've had a C90x intake before and it liked a shift point around 6800 with my old and different setup... and I did too....lol. I would love to hear your thoughts on what you might do differently on this build... add in the looks and nostalgia component too... I just found you today and I NEVER subscribe to any channels but I did today! Thanks and I can't wait for the road test video!
Scrap the 280H and get something more modern in there. If you want a hot 289 for a GT350 clone, you can do far better. I have a ton of experience with the P heads and I’d recommend 232°@.050 intake installed on a 112 ICL, and 238°@.050 exhaust with the cam ground on a 112° LSA. Intake lift with those heads should be in the .560” range on the intake and .540” on the exhaust. Use a conical spring in the 300lb/inch range that sets the seat pressure at 105-110 @1.800 installed height. Step up to a 1.90/1.60 valve package and port the bowls and the exhaust port, the intake just needs a nice blend. Mill the heads to set the chambers at 54cc. Deck the block to 8.190” and use a flat top piston like a Mahle or SRP with 2-eyebrow reliefs. Final compression will be close to 11:1, it will run fine on pump gas, have plenty of torque and it will scream to 7000. It will hit pretty good at idle and give the right impression at all times.
Scott, Food for thought. I had a 66 Fairlane with an 8 inch rear end. I had the pinion bearing support break which did a number to my ring and pinion. So, I hit the junk yards for a replacement case. I found a Fairlane that had a "WOR" style case (Heavy "Egg Crate" style exterior ribs (Like a 9 inch Nodular case) It had a much larger/Stronger pinion bearing Support ( the snout end opposite of the yoke end ). I tossed in 4:11 's . The built C4 1st to 2nd shift didn't hurt the 8 inch anymore.
@@creekjonsun thank you for the reply and info... I do have the extra ribbed 8 inch case. I've never broken a case only ever spit out spider gears. I have an early 9 but needs the little axle tubes installed... I'll do that at a later date... I just would like it to look as shelby correct as it can... for me only. It was a coupe c code that I'm converting to a fastback. My wife bought it for me so I'll never sell it.
@@scottford1091 the GT 350 used a "Bottle Neck" 9 inch housing . I had one in my 63 Ranchero. It was a GT 350 rear end. Make sure your spring perches are welded real good. Hot asphalt , Sticky tires and a hard launch tore my perches off the tubes bending the shaft and breaking my toploader's tail shaft housing. Traction bars probably would have saved my driveline.
@@creekjonsun I have an 8 inch with the bottleneck tube that I'm gonna swap onto my 66 9 inch housing and keep the stock 8 inch axles. Also I have under riders installed to help stop the twist and wheel hop. I also put gussets on the perches when I move them. I won't need to on this one though since I'm grabbing the whole tube. I'll still add the gussets though.
It is in fact a real Shelby. Most of these cars are modified or incorrect in some way, and value is only a concern to those who intend to sell the car, This one has been in the family 34-1/2 years, it’s not going anywhere. The “mods” as you’re calling them serve to make a car that isn’t really a concourse restoration candidate an extremely fun driver with no significant or irreversible impact on the car itself. If you’re a purist, this channel, and my car will not be to your liking and I would suggest joining the other purist curmudgeons on the SAAC forums.
@@TheGT350Garage I'm totally with you... an investor won't get what we do and love. When I get a new customer in my restoration/hot rod shop the first thing I tell them is that they are not making a deal with me, they are making a deal with their car. Their car is going to tell them how much it costs to get what they want, not me.
Thanks for sharing your knowledge. I’d like your input for my sbf. 10.2:1 static/swept volume compression, forged Mahle pistons(flat tops) low drag rings, 28oz /scat rotating assembly, torque plate honed, Blueprint 190cc aluminum heads w/60cc chamber(flow 250@.500 lift) 2.02/1.60 valves -as cast, Weiand Street Warrior intake, 1” open spacer, Comp XE266HR12 cam ((216/224 @ 050, 266/274 advertised, .544/ .555 lift w/ 1.6 full roller rockers) 600 cfm vac sec squats bore carb) 1-5/8” mid length ceramic coated headers, 32 degrees all in by 3000rpm, in a manual Bronco. Would a Weiand Stealth extend my rpm range? Do I need a bigger cam? More compression? Thx
If it’s a 302/306 it should make about 340-350hp at 5600-5800rpm with about 325-335tq at 3600-4200rpm. That’s at the flywheel not the tire. If it’s a 331 or 347, the horsepower will be 10-20 more but 200-400rpm sooner, and torque will be 20-40 more 200-400rpm sooner. In a Bronco anything in this range is a fairly ideal combination. More cam will hurt torque and require increasing the numerical gear ratio in the axles to utilize the extended rpm range.
Oh, and a 4-hole spacer might be a better choice than the open spacer. You can make a divider and convert it to a 2-hole and probably see a gain in torque. Your total timing is about ideal for that setup, hopefully you’re using vacuum advance on manifold vacuum to improve idle quality, reduce operating temperatures, and maximize fuel economy.
I teach automotive engine performance, computer controls, and emissions systems diagnostics for one of the largest automobile manufacturers in the world. I consider myself “retired” from being a technician or mechanic.
Master is reality. 1st sabbath album. Great one. Into the void one of my favorite.
It's funny you would pick a vacuum secondary carb and a single plane manifold. I've got a 450hp 293 that has over 400 ftlb of torque from 2800 to 5100 rpm. Guess what manifold is on it.
Hotrod magazine did a dyno test on the rpm airgap and the jr. where the jr gave up so much down low with relatively the same numbers as the airgap. If you need a single plane, and I don't believe you do, get the Victor....
Also I use a 750 mechanical carb, I tried a 600 dp the 750 made 9hp more at 6300rpm and 2 to 3 every where else...
The VIctor Jr will be extensively modified to fit my specific combination and needs. An RPM air gap falls off above 6500, my engine will want to turn 1000-1500rpm more than that . Unfortunately the Super Victor doesn’t fit under the stock hood profile.
As for the vacuum secondary carb, it’s a choice based on numerous factors, but as a street car and for use on a road course it offers the air and fuel control necessary for the power level and I have extensive experience with them for drivability purposes that make them more enjoyable to drive. A mechanical secondary would require more effort to tune, balancing the trade off between power and drivability. Your power difference was most likely entirely in fuel delivery and not an airflow difference, at that engine speed your displacement can only consume about 535cfm.
old mans powerboat really liked a 2 inch 4 hole spacer on his 302 on the victor junior with a 650 vacuum
Thank you. I have been contemplating getting a new manifold.
If you need any additional information to help you make your decision, feel free to ask for help.
Great points made.
Thanks for the overview. My dad drove nothing but Ford, but I'm into mopars. I enjoy your channel. While listening to your explanations, I dont disagree, though I am curious about a couple things. Why would Ford/Shelby design an intake with two signifcantly different lengths of runner, when edelbrock solution seems pretty obvious. I know Eddy airgaps are a pretty good choice for any steerable performance engine. There had to be a reason for the shelby runner length choice.. Would it to have been to broaden the powerband of the engine? I'd think there is a good chance. You quoted the power difference at peak HP of 15 or so between the shelby and the rpm airgap. That may be so, but peak numbers are for bragging, area under the curve is for winning and driveability. It would be interesting to see the graphs of these power curves to compare. Love your videos
The intake on the Shelby GT350 was designed at a time when they didn’t understand why the manifold made more power, they just observed that it did. It’s actually a little bit confusing “who” designed the manifold, Edelbrock sold the same manifold as the F4-B but early Shelby castings were made by other manufacturers.
The Shelby intake design was based on the same philosophy used on FE engines, which had low riser, medium riser, high riser, tunnel wedge, and tunnel port heads and intakes. While the ports on each head also changed, the manifold also changed, with the carburetor pads being raised incrementally in the thought that the air fuel mixture would have an improved “straighter” shot through the intake port at the valve.
Both the RPM and RPM Air Gap will make more power everywhere, not just up top, throttle response is better, torque is better, horsepower is better. They distribute the air fuel mixture more effectively and their ports are more efficient and can move a larger quantity of the air fuel charge with less restriction. If you run both intakes on the same engine for the same test, both the average power and peak power will show the Shelby manifold is inferior, not just the peak numbers.
@@TheGT350Garage thank you kindly for the detailed reply.
Also, you mentioned going with a traction loc diff. No Detroit locker? Too noisy or not in your car? Just curious. And if you still have your locker would you sell it?
My car was a 28-spline open differential like most GT350s in 1966. The Detroit Locker is fine for drag racing but noisy on the street. The Traction Lock is smooth and quiet and does well overall, but has some limitations. If I’m not happy with it in my various uses, I’ll probably install a Torsen T1 geared type differential. On a car like mine that is will be a serious driver, originality is not quite as important.
maybe trim the bread up to the top of the Black Sabbath letters on your shirt, lmao just poking fun. My 65 coupe , Feb of 65 is WIMBLETON White , I read after april 65 you couldn't get this Color because of Shelby , & the Gt-350's the coupe's white was a delete or changed ?. I did a flat tappet & it Burnt up, Now everything is Retro roller !! no break in is he Key!! I'm using a Edlebrook #2221 cam .520 lift & Dura. @ .050: 227°/234° ! very streetable.
Hydraulic roller is the way to go these days, I’ll be running one in my combination. What a lot of guys don’t realize is the hydraulic roller with equal specs to a mechanical or hydraulic flat tappet cam the hydraulic roller at higher lifts has significantly more duration, as much as 30-50° at .200” to .500”+ valve lift.
As for Wimbledon White, it was a staple color for Ford throughout the ‘60s and ‘70. Even when other whites were available during the period It was available. It was never considered a “Shelby exclusive” color.
Use a 351w firing order camshaft for a better outcome.
It doesn’t really matter. You still have a pair of cylinders firing successively on the both banks. With 1-5-4-2-6-3-7-8 you have 4-2 and 7-8
With 1-3-7-2-6-5-4-8 you have 1-3 and 6-5
Overlay the firing order between a Chevrolet V8 and a Ford V8 and you’re in for a surprise, the only reason the firing orders are different is because of the cylinder numbering, but they actually fire in the same exact sequence. And Chevrolet’s firing order swap was no different from Ford’s. It’s truly a moot point for power production.
Fabulous video. I am building a fake gt350. I have a 289 .030 calculating maybe 10:1 with gt40p heads and 120lbs seat pressure..roller rockers with screw in plugs just because... Old school comp 280h flat hyd. Cam. I had an F4B but am ditching it for the upgraded blue thunder Cobra moniker intake. Also I'm running a 4.11 in the 8 inch with an auburn diff. Think I could expect 325+ horsepower? That's my goal. I know the p heads peter out at around those numbers. I've had a C90x intake before and it liked a shift point around 6800 with my old and different setup... and I did too....lol. I would love to hear your thoughts on what you might do differently on this build... add in the looks and nostalgia component too... I just found you today and I NEVER subscribe to any channels but I did today! Thanks and I can't wait for the road test video!
Scrap the 280H and get something more modern in there. If you want a hot 289 for a GT350 clone, you can do far better. I have a ton of experience with the P heads and I’d recommend 232°@.050 intake installed on a 112 ICL, and 238°@.050 exhaust with the cam ground on a 112° LSA. Intake lift with those heads should be in the .560” range on the intake and .540” on the exhaust. Use a conical spring in the 300lb/inch range that sets the seat pressure at 105-110 @1.800 installed height. Step up to a 1.90/1.60 valve package and port the bowls and the exhaust port, the intake just needs a nice blend. Mill the heads to set the chambers at 54cc. Deck the block to 8.190” and use a flat top piston like a Mahle or SRP with 2-eyebrow reliefs. Final compression will be close to 11:1, it will run fine on pump gas, have plenty of torque and it will scream to 7000. It will hit pretty good at idle and give the right impression at all times.
Scott, Food for thought. I had a 66 Fairlane with an 8 inch rear end. I had the pinion bearing support break which did a number to my ring and pinion. So, I hit the junk yards for a replacement case. I found a Fairlane that had a "WOR" style case (Heavy "Egg Crate" style exterior ribs (Like a 9 inch Nodular case) It had a much larger/Stronger pinion bearing Support ( the snout end opposite of the yoke end ). I tossed in 4:11 's . The built C4 1st to 2nd shift didn't hurt the 8 inch anymore.
@@creekjonsun thank you for the reply and info... I do have the extra ribbed 8 inch case. I've never broken a case only ever spit out spider gears. I have an early 9 but needs the little axle tubes installed... I'll do that at a later date... I just would like it to look as shelby correct as it can... for me only. It was a coupe c code that I'm converting to a fastback. My wife bought it for me so I'll never sell it.
@@scottford1091 the GT 350 used a "Bottle Neck" 9 inch housing . I had one in my 63 Ranchero. It was a GT 350 rear end. Make sure your spring perches are welded real good. Hot asphalt , Sticky tires and a hard launch tore my perches off the tubes bending the shaft and breaking my toploader's tail shaft housing. Traction bars probably would have saved my driveline.
@@creekjonsun I have an 8 inch with the bottleneck tube that I'm gonna swap onto my 66 9 inch housing and keep the stock 8 inch axles. Also I have under riders installed to help stop the twist and wheel hop. I also put gussets on the perches when I move them. I won't need to on this one though since I'm grabbing the whole tube. I'll still add the gussets though.
Is this an actual shelby? Looks as if it is being devalued with all the mods.
It is in fact a real Shelby. Most of these cars are modified or incorrect in some way, and value is only a concern to those who intend to sell the car, This one has been in the family 34-1/2 years, it’s not going anywhere. The “mods” as you’re calling them serve to make a car that isn’t really a concourse restoration candidate an extremely fun driver with no significant or irreversible impact on the car itself. If you’re a purist, this channel, and my car will not be to your liking and I would suggest joining the other purist curmudgeons on the SAAC forums.
@@TheGT350Garage I'm totally with you... an investor won't get what we do and love. When I get a new customer in my restoration/hot rod shop the first thing I tell them is that they are not making a deal with me, they are making a deal with their car. Their car is going to tell them how much it costs to get what they want, not me.
Thanks for sharing your knowledge. I’d like your input for my sbf.
10.2:1 static/swept volume compression, forged Mahle pistons(flat tops) low drag rings, 28oz /scat rotating assembly, torque plate honed, Blueprint 190cc aluminum heads w/60cc chamber(flow 250@.500 lift) 2.02/1.60 valves -as cast, Weiand Street Warrior intake, 1” open spacer, Comp XE266HR12 cam ((216/224 @ 050, 266/274 advertised, .544/ .555 lift w/ 1.6 full roller rockers) 600 cfm vac sec squats bore carb) 1-5/8” mid length ceramic coated headers, 32 degrees all in by 3000rpm, in a manual Bronco.
Would a Weiand Stealth extend my rpm range? Do I need a bigger cam? More compression?
Thx
What's your cid?
If it’s a 302/306 it should make about 340-350hp at 5600-5800rpm with about 325-335tq at 3600-4200rpm. That’s at the flywheel not the tire. If it’s a 331 or 347, the horsepower will be 10-20 more but 200-400rpm sooner, and torque will be 20-40 more 200-400rpm sooner. In a Bronco anything in this range is a fairly ideal combination. More cam will hurt torque and require increasing the numerical gear ratio in the axles to utilize the extended rpm range.
Oh, and a 4-hole spacer might be a better choice than the open spacer. You can make a divider and convert it to a 2-hole and probably see a gain in torque. Your total timing is about ideal for that setup, hopefully you’re using vacuum advance on manifold vacuum to improve idle quality, reduce operating temperatures, and maximize fuel economy.
@@TheGT350Garage 3.73 gears on 35s BUT, my 1st gear is 6.69:1 which I use sometimes, revs out quick to 10 mph, 😂
@@TheGT350Garage 331
So, What is your daytime job?
I teach automotive engine performance, computer controls, and emissions systems diagnostics for one of the largest automobile manufacturers in the world. I consider myself “retired” from being a technician or mechanic.