Anyone here run the Comp Cams Thumper cam in there SB

[67coroneter]

Have a 67 Coronet with 318, want to run the smallest of the hydraulic Thumper cam from Comp cams, I see you can't run stock valve springs with this cam, but it also says with using Comp Cams valve springs for this cam, machining is required, anyone else here run this cam with there Mopar small block motor without machining and what machining needs to be done

 

[YY1]

Take a look at the Summit 6900/6901.

Actually good performance cams.

Depending on who you talk to, you can run the stock springs with no machining (the lift is within stock spec), and there are many vids on the net with sound where you can hear a healthy mild lope.

 

[Mike67]

One question i have is whats the life span of factory springs? Is there a a specific minimum pressure rating where they are recommended to be replaced... is 10% drop is acceptable?
Just curious

 

[toolmanmike]

What springs does Comp recommend?

 

[moper]

Comp recommends the 995-16 spring. That's a dual spring assembly that requires the spring seats and guides be machined to fit them. My advice - do yourself a HUGE favor and list the intended use of the engine (be honest with what you plan to do with it) and a better cam can be recommended. Thumpers are the wrong cam for pretty much anything. They do make for a bad idle. Which makes no power anywhere else. Camshafts are bought for wwhat they will do, nto what they might sound like.

 

[toolmanmike]

If you want that nasty idle, check out Hughes Whiplash cams. Here's a 318 in the video and a link to their website. Their 318 cam recommends a single spring with dampner.
http://www.hughesengines.com/Index/...hZnQ=&level2=V2hpcGxhc2ggTXVzY2xlIENhciBDYW1z

 

[mentor70]

as stated above, these cams have very abstract timing events, i recently built a 5.0 SBF for my 77 F100 pickup, i went with a Howards "Rattler" cam, (which is the same company that makes the Whipflash cams for Hughes) and it was a HUGE disappointment.

Idle was bad ***, but no bottom end, no manifold vacuum, 9-10 at idle in neutral, 5-6 in gear, shitty pig rich idle because due to the carbs power valve was a 6.5. NOTHING BUT DRAMA.

i pulled it out and installed a Lunati Voodoo roller similar size, gained 5 inch of manifold vacuum in idle to make around 14-15 inches, Rockstar throttle response, carb loved it, got loads of bottom end, nice muscle car idle.

personally, id look for a good dual pattern cam that matches what you want to do with the car.

 

[petieg383]

as stated above, these cams have very abstract timing events, i recently built a 5.0 SBF for my 77 F100 pickup, i went with a Howards "Rattler" cam, (which is the same company that makes the Whipflash cams for Hughes) and it was a HUGE disappointment.

Idle was bad ***, but no bottom end, no manifold vacuum, 9-10 at idle in neutral, 5-6 in gear, shitty pig rich idle because due to the carbs power valve was a 6.5. NOTHING BUT DRAMA.

i pulled it out and installed a Lunati Voodoo roller similar size, gained 5 inch of manifold vacuum in idle to make around 14-15 inches, Rockstar throttle response, carb loved it, got loads of bottom end, nice muscle car idle.

personally, id look for a good dual pattern cam that matches what you want to do with the car.

What was the rest of your combo like in the truck? Compression? What size carb? Stall speed? Rear gears? Was the Rattler a roller cam or just a normal flat tappet, because that should be a big difference in itself. You can't just condemn the Whiplash-type cam without more info. A lot of people love them and the idle isn't the only reason.

 

[mentor70]

the 5.0 in my truck is a 1988 Mustang GT engine as a base, so yes its a hydraulic roller cam. Trick Flow 170 heads, 58cc 10.25 compression. 2k converter (as Howards recommended), with 3.70 gears and a 650 Holley HP.

i didnt notice much interest in these types of cams in the Ford community, but IMO they are kind of a novelty cam. not intended for serious performance

i made a soild effort to tune around the cam, smaller power valve (3.5) messing with timming and carb adjustments.

all that was left was to mess with cam phasing, but at this point, faced with pulling the timing cover off, i really had to put some serious thought as to how many times i wanted to be pulling that cover off if my alterations failed.

not having any experiance with that type of cam, i decided to pull it and go with my first choice from the get go, Lunati Voodoo.

yes, i have much regret...lol