Chevy

Don Jacks

Well Seasoned Member
Supporting Member 3
#4
There have been at least a dozen people that I've personally talked to that had put a Thumper Cam in their W engine and NONE have liked it,all of them changed to something else and were then happy.Thumper cams are made for noise not drivability or effecincy.A good hyd.flat tappet choice would be the 0951 from Show Cars.Your existng springs might be ok depending on the seat and open pressures and how much lift before they go into bind.You'd need to check that.
 

1964SuperStocker

Well Known Member
Supporting Member 2
#9
Don I think there is one person who runs a thumper successfully. His drivetrain has enough broken parts to prove it at least works with his combination!
"Runs a thumper successfully" isn't the same as gets the best power out of "his combination". The only point Don was making is the vast majority of people who have run the "Thumper series" decide that the "noisy thump" they make isn't as imporant as the performance that could be achieved by simply selecting a better camshaft suited to their build. When a company advertises an item to do something as specific as make noise.

"COMP Cams is bringing the musclecar sound back, and it's nastier than ever! Let's face it--few things serve to grab our attention at a car show or cruise night more than a car with a thumping, high performance idle. In fact, one of the most frequent questions fielded when customers call our tech line is, "What camshaft will give my car that mean-sounding idle?" In an ongoing quest to provide you with the performance and sound you demand, COMP Cams engineering team proudly introduces the Thumpr series cam and lifter kits. The lobe profile and grind characteristics of these new Thumpr camshafts use a combination of an early exhaust valve opening, a long exhaust duration, and a generous amount of intake and exhaust overlap to maximize the rough-idling characteristics of the cams. This gives you a seriously aggressive exhaust note without negatively impacting the power output or streetability of the engine. Thumpr camshafts are available in different grind profiles; each one will produce a rough, racy exhaust note and impressive amounts of horsepower and torque within a different rpm range. These Thumpr series cam and lifter kits deliver a substantial power increase over an identical hydraulic flat tappet grind without sacrificing reliability or ease of maintenance."

When you buy a sound maker, you are leaving performance on the table. Not to say that is bad to the person that likes to make more noise. I was beat last year drag racing by a car running a thumper.
 

Don Jacks

Well Seasoned Member
Supporting Member 3
#10
I'm sorry if I offended Denson1932 in any way.Yes I've heard that Rick has one in his track only application.I'm referring to a street driven engine that's main normal rpm band is in the under 4,000 range and it has street gearing.That's not where they were designed to work the best so why put them in there.They may set off car alarms but they lack low rpm torque,they are sluggish until the rpm come up and the gas mileage and plug life suffer.They can and do make decent horse power numbers,but higher in the rpm band,not so good down where the engine is actually used most of the time.
 

pvs409

Well Known Member
Supporting Member 8
#11
Yes I have a Comp Cams -Thumper Cam that I won Iowa with last year in my 62 Impala SS hardtop.

Yes its very noisy idling, will not idle good below about 1200 RPM.
It makes 530 HP and 590 Ft # of torque on the engine dyno at my Machine Shop -at 5500 RPM..

With 474 cubic inches with Eagle stroker Crank and big block rods and ported Edelbrock Heads(30 CFM increase in flow over stock -on flow bench) and dual Edelbrock 600 CFM carbs on a stock 2-4 intake.

the cam is .526 intake lift and .510 exhaust lift with 107 lobe separation

So far no broken rear ends... In fact I have never blown a posi rear end ever drag racing my 57(270 HP), my 59 (315 HP) my & my 62 (327/300), that started in the 1960's ended in 1980s and started again occasionally in 2014 to now.

I just switched from a Muncie 4 speed to a Richmond 5 speed and the car feels much faster. Have to do a 500 mile clutch break in
and now I have a broken trunk hinge preventing me from driving the car(trunk is off car)
Paul
 

Rickys61

Well Known Member
Supporting Member 3
#12
I have a Thumper hydraulic roller that I run with solid lifters in the 380... 565 int. 584 exh 230/242 duration at .050 on the 107 lobe separation. It actually does the opposite as described, The car has a best 60’ of 1.67, but runs out of steam at the big end. I’m not sure if it’s the cam, carbs, intake or the heads aren’t moving enough air up high RPM.... I’ve got some more experimenting to do before I condemn the cam...:scratch
Yea... the car likes to break parts....but that’s all part of the game I guess...:dunno
 

64ss409

Well Known Member
Supporting Member 9
#13
I have been wondering about trying the Thumper cam that Paul is using. I have been using the Show Cars 0920 cam, Isky CH 296 Hydraulic, 515 lift. It pulls good, sounds good. I tried the 0951 cam 2 years ago hoping for a little more bottom end. Bottom end was about the same, but lost .2 in the 1/4, so went back to the 0920 cam.
 

benchseat4speed

Well Known Member
Supporting Member 4
#14
I’m with Don and superstocker. I’m all about tight lobe centers but, that duration split on those thumpr cams is HUGE, and the overlap always favors the exhaust side for that ‘lumpy idle.’ Engines nowadays pull to 6000+ and idle like sewing machines....who cares what the idle sounds like!! How’s it run from 1000 to the rev limiter! I have a hydraulic roller from crane, custom grind, conservative specs, and it pulls hard to 6500. ‘Lumpy idle’ was the last thing I cared about.
 
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