I know I'm 5yrs late, but it sounds like your problem is your butterflies are open passed your transition slot, which will cause rich idle from your main jets, rather than just your idle circuit, you my have to drill holes in the butterflies in order to close the main circuit during idle, this is the case for many large cams with rough idle, hope this helps.
As a suggestion on timing. Modify or get an adjustable vacuum advance can. Adjust it so by it's self it adds say 10*degrees, for starters. then drop you initial advance down to 4* for starters, with out any vacuum advance connected. Now connect vac advance to full time vacuum. Now with the low initial the motor cranks over real easy, especially when hot. Once it catches on start the full time vac advance kicks in and your ignition timing at idle will jump up to the 12-14-16 you need. you can tweak the initial and vac advance amount up and down to and sneak up on the sweet spot. Then you can sneak up on the correct idle mixture that works. Then you can sneak up on centrifugal advance rate, slowly that works best. Then Idle speed adjustments. When you got it right it will be rock solid, with no need to fiddle.
that's interesting way of using the controls to apply the timing you want to the engine when you want it. 😊 makes sense on the easy starting, old cars use to do these adjustments by hand for starting.
@@DANTHETUBEMAN I have the Chevy Performance basic 260 hp crate 350 in my v8 8 s-10 Blazer. It's stock except for Edelbrock performer cam, intake and basic 600 holley carb. The cam instructions call for 14 to 16 degrees of initial for a small cam. The setup I use starts easily every time, Idles at 20 inches, and cruises the highway at speed with very very little pedal. I can't imagine going back to ported advance and hard cranking hot starts. This should help on thumpy cams too. More vacuum at idle less idle speed, leaner mixture at idle better drive-ability. Give it a try it's a winner.
What gearhead doesn't like a decent cam... When Comp came up with the Thumpr family of cams, they wanted to de-mystify cam selection based on your driving and performance needs. You could pick 'mild' 'medium' or 'wild'. They offered kits and technical advice so even weekend warriors could get that cam sound we wanted, along with daily driver reliability. For the most part, Comp succeeded and the name Thumpr is synonymous with quality with big wow factor. Every engine set-up is different so cam set-up is different too. Some 'fine tuning' might be necessary and a bit of patience goes along ways. I had a friend call me up once and asked me if I had ever installed cams before. I said sure, a few times. He asked me to come over and help. Get over and his car is on driveway with hood up. In Seattle at the time and it rains all winter there. Pull old cam, install new. Soaked to the skin. Starts almost instantly. Fine tuning takes rest of day. Have never installed a cam in the rain ever since... geesh.
The comp cam I had in my 77 camaro pn 12-600-4 intake .479 exhaust.465 so be careful vortec can’t take that much lift I’m working on a set right now with the ls6 spring and comp cams locks and retainers
You should look into installing a Thompson Performance PowerBlast plate into that Holley. I can tell the throttle response is good but it's lacking the crispness that common with EFI engines. The plate also will atomize your fuel as it changes the spray pattern when it exits the squirters and enters the bowl. It basically mists the fuel instead if squirting a stream. By doing that,you'll reduce the amount of fuel needed to power the engine in turn improving fuel mileage. It comes in handy when you're running that much of a stall.
I like the work you did the engine look good but you need to upgrade the heads on it..those are old truck heads,they don't flow good. you need a set of cast-iron 64cc vortec heads, and you'll be right where you need to be.
Don't try to run any of the thumpr cams with a stock torque converter , it will shake and shudder at idle in gear so bad your teeth will fall out. Initial 16 to 18 total 36 to 38. Timing actually a little rich works better . The amount of overlap is what makes them hard to tune. But your sounds pretty spot on .
Thanks for the comment and you are correct and also the torque converter can't be tight or that will also be an issue, the cam is a hard one to tune but timing is not even half of it, to me vacuum plays a huge issue as well as having the carb properly set up. Although people say this cam is about sound it does have some power to it and its fun!!
I have a real solver problem . How did you adjust the valve lash . My cam is a thumper and is not thumpering ,,, I set the lash on stock camshaft . Having a real problem. ?!!
I set the lash or adjusted to valves by simply using the chevy method of loosening the valves as the engine is running till it taps lightly the slowly tighten it up till it stops then I did a half turn. I have did this on all flat tappet cams I have used.
thanks for the info! im going to do this weekend after i stop by summit for the secondary springs. what did you set up first ? Did you set up base timing first then adjust the carb? or did you did you set up the carb first then base timing?
I did base timing then total, then I adjusted the carb, just remember idle is 900- 1000 rpm and I have 9:5 compression so ur idle may be different depending on ur set up, txt if u have any questions.
Im going with the thumpr cam but no stall. Its a mild cam. Summit says i wont have to change anything as far as torque converter or rear end is concerned. Any thoughts?
Depends on your setup but the cam profile says it doesn't require a stall and gears I have seen people run it without those but of course to get bang for the buck I recommend at least 2500 stall and gears later, my biggest issue was dialing in the timing and getting a good idle which required changing my power valve and secondary springs. Overall it's all in your setup, what's your setup gonna be?
MrVigor47 I got Comp Cam springs, Thumpr cam @ 50. Double roller chain, high volume mellings oil pump, water pump, rings, bearings, and lifters. I believe they said something about rpm being from 7 - 14
Also its going to be a daily driver that i rarely drive. So i wont be racing this thing. Just for cruising, lil extra torque and hp. Pulling the 305 engine out this week
It didn't wanna spin at the time most likely because the starter isnt powerful enough to overcome that type of cylinder pressure. a powermaster starter would have probably solved it. these cams like/need a lot of initial timing. ive heard people run 18 degrees initial or more on them. All in at 2500. low intial timing on a big cam will make it run hotter big duration or big overlap cams like these thumprs like a lot of initial timing to get the cylinder pressure up to have that peppy low end. They get a bad rep because people dont know a lot about ignition timing curves.
U r right, I actually have a powermaster starter on my engine although I'm learning about timing myself and a I know it's critical with alot of cams, thanks for the comment
@@MrVigor47 yeah no doubt its a learning curve and even though used to work on cars and went to school for it, it's a sifferent ball game with performance engines although a lot of us at the time were trying to hop up our cars and the teachers knew a lot about it but we just learned more about normal repair Another thing I leanred is that if you don't have enough initial most people will mess around with the idle soeed screw to get it to work right But if you open the throttle blades too much doing that it will run on when you try to turn the engine off. I heard the hot ticket is more initial than mechanical advance all in at 2500 (2000 may be too low 3000 may be too high 2500 just right) and about 10 degrees vacuum advance. I'm gonna attempt this on the car on my channel when I get the 302 engine redone
I have the Holley 4160 but I had to change the power valve and secondary spring for this cam. In the Edlebrock you many have to change the metering rods and jets.
@@MrVigor47 might have to try that one. I'm running same serpentine system but a Camaro upper hose so it runs through the front and comes very close to the belt.
These are actually the Summit Racing Vortec heads so I didn't have to get any machine work done but I do have some stock Vortec heads that I had to have the bosses cut down and I used screw in studs with them. You also have to have self aligning rockers.
@@MrVigor47 yeah I see a lot of videos where people are trying to idle 230 duration cams at 750...that's stock. you don't have stock lol sounds good man. a 230 duration cam usually needs 10:1 and a 3000 stall no matter what the book says. the duration in different engines will act different but part of that is head size. voretcs are 170 and are more like 220 @.050 and less than 10:1 but you almost cant beat them for budget I bet if you put a 180 head on it you'll pick up even more. doesn't even have to be an afr head, just like a promaxx head and buy it bare. supposed to be good. 183cc MAXX heads. but a 230 @.050 in a 350 is definitely a 3000-6000 rpm camshaft. runs good man I like it.
Bruh is there a way to message you directly or do you have a Instagram? I have a 87 cutlass small block 350 with the same exact cam and I’m trying to figure out how to get the timing correct I just had the exhaust connected so it’s time for timing so I was told..I’m just ready to drive my damn car fr lol
People say the thumper cam sounds good....not sure if its youtube audio but it sounds like the engine is stabling at idle to the point it nearly sounds like its missing at idle......its not a great sound you would expect from a camed 350, you could be right it could be idle control in the carby.........not picking on you....they all sound similar Bro...... th-cam.com/video/JDPwY0LbRVY/w-d-xo.html
!["สนธิ" ห่วงมีขบวนการปกป้อง "ทนายตั้ม" : [THE MESSAGE]](http://i.ytimg.com/vi/2GQNp3EoMc0/mqdefault.jpg)
I know I'm 5yrs late, but it sounds like your problem is your butterflies are open passed your transition slot, which will cause rich idle from your main jets, rather than just your idle circuit, you my have to drill holes in the butterflies in order to close the main circuit during idle, this is the case for many large cams with rough idle, hope this helps.
As a suggestion on timing. Modify or get an adjustable vacuum advance can. Adjust it so by it's self it adds say 10*degrees, for starters. then drop you initial advance down to 4* for starters, with out any vacuum advance connected. Now connect vac advance to full time vacuum. Now with the low initial the motor cranks over real easy, especially when hot. Once it catches on start the full time vac advance kicks in and your ignition timing at idle will jump up to the 12-14-16 you need. you can tweak the initial and vac advance amount up and down to and sneak up on the sweet spot. Then you can sneak up on the correct idle mixture that works. Then you can sneak up on centrifugal advance rate, slowly that works best. Then Idle speed adjustments. When you got it right it will be rock solid, with no need to fiddle.
that's interesting way of using the controls to apply the timing you want to the engine when you want it. 😊
makes sense on the easy starting, old cars use to do these adjustments by hand for starting.
@@DANTHETUBEMAN I have the Chevy Performance basic 260 hp crate 350 in my v8 8 s-10 Blazer. It's stock except for Edelbrock performer cam, intake and basic 600 holley carb. The cam instructions call for 14 to 16 degrees of initial for a small cam. The setup I use starts easily every time, Idles at 20 inches, and cruises the highway at speed with very very little pedal.
I can't imagine going back to ported advance and hard cranking hot starts. This should help on thumpy cams too. More vacuum at idle less idle speed, leaner mixture at idle better drive-ability. Give it a try it's a winner.
It's good to see you have you're car on the road now bro. She sounds really good. Keep up the good work👌👍
What gearhead doesn't like a decent cam...
When Comp came up with the Thumpr family of cams, they wanted to de-mystify cam selection based on your driving and performance needs. You could pick 'mild' 'medium' or 'wild'. They offered kits and technical advice so even weekend warriors could get that cam sound we wanted, along with daily driver reliability. For the most part, Comp succeeded and the name Thumpr is synonymous with quality with big wow factor.
Every engine set-up is different so cam set-up is different too. Some 'fine tuning' might be necessary and a bit of patience goes along ways.
I had a friend call me up once and asked me if I had ever installed cams before. I said sure, a few times. He asked me to come over and help. Get over and his car is on driveway with hood up. In Seattle at the time and it rains all winter there. Pull old cam, install new. Soaked to the skin. Starts almost instantly. Fine tuning takes rest of day.
Have never installed a cam in the rain ever since... geesh.
The comp cam I had in my 77 camaro pn 12-600-4 intake .479 exhaust.465 so be careful vortec can’t take that much lift I’m working on a set right now with the ls6 spring and comp cams locks and retainers
Nice I'm doing the same thing not sure which cam
You should look into installing a Thompson Performance PowerBlast plate into that Holley. I can tell the throttle response is good but it's lacking the crispness that common with EFI engines. The plate also will atomize your fuel as it changes the spray pattern when it exits the squirters and enters the bowl. It basically mists the fuel instead if squirting a stream. By doing that,you'll reduce the amount of fuel needed to power the engine in turn improving fuel mileage. It comes in handy when you're running that much of a stall.
Send me the link to check it out
I like the work you did the engine look good but you need to upgrade the heads on it..those are old truck heads,they don't flow good. you need a set of cast-iron 64cc vortec heads, and you'll be right where you need to be.
Don't try to run any of the thumpr cams with a stock torque converter , it will shake and shudder at idle in gear so bad your teeth will fall out. Initial 16 to 18 total 36 to 38. Timing actually a little rich works better . The amount of overlap is what makes them hard to tune. But your sounds pretty spot on .
Thanks for the comment and you are correct and also the torque converter can't be tight or that will also be an issue, the cam is a hard one to tune but timing is not even half of it, to me vacuum plays a huge issue as well as having the carb properly set up. Although people say this cam is about sound it does have some power to it and its fun!!
I have a real solver problem . How did you adjust the valve lash . My cam is a thumper and is not thumpering ,,, I set the lash on stock camshaft . Having a real problem. ?!!
I set the lash or adjusted to valves by simply using the chevy method of loosening the valves as the engine is running till it taps lightly the slowly tighten it up till it stops then I did a half turn. I have did this on all flat tappet cams I have used.
Sounds pretty good
thanks for the info! im going to do this weekend after i stop by summit for the secondary springs. what did you set up first ? Did you set up base timing first then adjust the carb? or did you did you set up the carb first then base timing?
I did base timing then total, then I adjusted the carb, just remember idle is 900- 1000 rpm and I have 9:5 compression so ur idle may be different depending on ur set up, txt if u have any questions.
Im going with the thumpr cam but no stall. Its a mild cam. Summit says i wont have to change anything as far as torque converter or rear end is concerned. Any thoughts?
Depends on your setup but the cam profile says it doesn't require a stall and gears I have seen people run it without those but of course to get bang for the buck I recommend at least 2500 stall and gears later, my biggest issue was dialing in the timing and getting a good idle which required changing my power valve and secondary springs. Overall it's all in your setup, what's your setup gonna be?
MrVigor47 I got Comp Cam springs, Thumpr cam @ 50. Double roller chain, high volume mellings oil pump, water pump, rings, bearings, and lifters. I believe they said something about rpm being from 7 - 14
MrVigor47 its a vortec with tbi truck injector setup, going in 89 caprice LS Brougham with 373 gears and 200 metric transmission
Also its going to be a daily driver that i rarely drive. So i wont be racing this thing. Just for cruising, lil extra torque and hp. Pulling the 305 engine out this week
It didn't wanna spin at the time most likely because the starter isnt powerful enough to overcome that type of cylinder pressure. a powermaster starter would have probably solved it.
these cams like/need a lot of initial timing. ive heard people run 18 degrees initial or more on them. All in at 2500. low intial timing on a big cam will make it run hotter big duration or big overlap cams like these thumprs like a lot of initial timing to get the cylinder pressure up to have that peppy low end.
They get a bad rep because people dont know a lot about ignition timing curves.
U r right, I actually have a powermaster starter on my engine although I'm learning about timing myself and a I know it's critical with alot of cams, thanks for the comment
@@MrVigor47 yeah no doubt its a learning curve and even though used to work on cars and went to school for it, it's a sifferent ball game with performance engines although a lot of us at the time were trying to hop up our cars and the teachers knew a lot about it but we just learned more about normal repair
Another thing I leanred is that if you don't have enough initial most people will mess around with the idle soeed screw to get it to work right
But if you open the throttle blades too much doing that it will run on when you try to turn the engine off.
I heard the hot ticket is more initial than mechanical advance all in at 2500 (2000 may be too low 3000 may be too high 2500 just right) and about 10 degrees vacuum advance.
I'm gonna attempt this on the car on my channel when I get the 302 engine redone
I’m wanting to run this on a stock 350. They said it would work as long as I do the strings. Just wanting some input.
@port nut I used the thumpr cam the lowest one and it runs really good with my k10 so far and sounds good.
I have the same motor and cam with a edlebrock bro i need help it keeps cutting off when it gets hot i see you say go Holley which one
I have the Holley 4160 but I had to change the power valve and secondary spring for this cam. In the Edlebrock you many have to change the metering rods and jets.
I have the com cam k12 mutha thumpr on a sbc355. Have a holley 750 but like i try to put it at 36 total but it doesnt like it, i have 3600 stall
I would try 34 but I did change the spring in the secondary
@MrVigor47 I have the kit, but not sure what to change it to since it's a 750
they add 4 degrees adv. in the cam when cut BMT anyways
Did you have to go with 1.6 rockers on your vortecs to run that cam?
No, I got 1.5 roller tips. The valve train has everything pretty much listed in the cam profile.
nice ass set up bro keep it up
Happen to remember what your upper radiator hose is out of?
Believe it was a 81 Cutlass or 87 Monte Carlo
@@MrVigor47 might have to try that one. I'm running same serpentine system but a Camaro upper hose so it runs through the front and comes very close to the belt.
Right, my serpentine system is off a Camaro and I believe it us the hose for the Cutlass and I may have had to cut it a little bit
Great video sounds good. Idle little high when put it in gear. Did you modify your vortec heads cause they can take that much lift what cam number
These are actually the Summit Racing Vortec heads so I didn't have to get any machine work done but I do have some stock Vortec heads that I had to have the bosses cut down and I used screw in studs with them. You also have to have self aligning rockers.
Cam is supposed to idle about 900-1000 any thing lower it will not run in gear, thats what comp cam said
@@MrVigor47 yeah I see a lot of videos where people are trying to idle 230 duration cams at 750...that's stock. you don't have stock lol sounds good man. a 230 duration cam usually needs 10:1 and a 3000 stall no matter what the book says. the duration in different engines will act different but part of that is head size. voretcs are 170 and are more like 220 @.050 and less than 10:1 but you almost cant beat them for budget
I bet if you put a 180 head on it you'll pick up even more. doesn't even have to be an afr head, just like a promaxx head and buy it bare. supposed to be good. 183cc MAXX heads. but a 230 @.050 in a 350 is definitely a 3000-6000 rpm camshaft. runs good man I like it.
music to my ears
Bruh is there a way to message you directly or do you have a Instagram? I have a 87 cutlass small block 350 with the same exact cam and I’m trying to figure out how to get the timing correct I just had the exhaust connected so it’s time for timing so I was told..I’m just ready to drive my damn car fr lol
I'll send u my Instagram, just gotta look it up
nicksmith3270
SMOOV
Thx for watching!!
I think she purring like a kitten
Hey, is that a stock motor???
Yep besides being bored .40 (357). Stock bottom with Vortec heads, valve train is completely comp cams.
Needs some cherry bomb mufflers.
People say the thumper cam sounds good....not sure if its youtube audio but it sounds like the engine is stabling at idle
to the point it nearly sounds like its missing at idle......its not a great sound you would expect from a camed 350, you could be
right it could be idle control in the carby.........not picking on you....they all sound similar Bro......
th-cam.com/video/JDPwY0LbRVY/w-d-xo.html
Hp