Thumpr cam crap

-
Sorry, that 396 sounds better. lol That joker is talkin the talk. That red car sounds good though.
 
comp mutha thumper roller cam.JPG

ever body hate'in on the thumper cams, but i got this roller at a deal and got a factory roller cam 318 motor with 86,000 g'ma miles on it! cant wate to try it out my self and see, alta lest sound wicked threw open fender well headers!
 
SGBARRACUDA said:
Hey Rob, is that the SS Chevelle that was in your yard years ago?
Click to expand...

Naw, that one is gettin a nuts and bolts total restoration. It's just right down the road. Already got it in primer.
 
Well I give up! This Thumpr cam is nothing but crap. Checked for vacuum leaks even hooked the Guage to the dipstick tube and no leaks. Played with my idle timing and af mixture which do change so I know it's on the idle circuit. I have spent too much time just on this crap. I'm done, going with a Lunati cam like I should of from the beginning and get the bark with the bite.
 
N1ce2k1llu said:
Well I give up! This Thumpr cam is nothing but crap. Checked for vacuum leaks even hooked the Guage to the dipstick tube and no leaks. Played with my idle timing and af mixture which do change so I know it's on the idle circuit. I have spent too much time just on this crap. I'm done, going with a Lunati cam like I should of from the beginning and get the bark with the bite.
Click to expand...
Harold Brookshire designed it ,if your looking at Voodoo..
A great line of camshaft.
 
My thought....I would look else where for a cam...MP cams are priced beyond STUPID.......
 
They can be had for reasonable money if you do your homework and know what you're looking for...patience grasshopper...:D
 
before we decide it is crap, u need to throw a degree wheel on it. (it is too much cam for your combo, and I would never buy one, I think they are dumb.) Install it around 105* intake centerline
 
No reason to buy an old Mopar-grind these days when better and newer developed stuff is out there.

As for the OP's cam issues;
I suspect some sparkwires are still mixed up, there's a vacuumleak somewhere or the cam is installed way off perhaps.
 
dirty white boy said:
View attachment 1715164022
ever body hate'in on the thumper cams, but i got this roller at a deal and got a factory roller cam 318 motor with 86,000 g'ma miles on it! cant wate to try it out my self and see, alta lest sound wicked threw open fender well headers!
Click to expand...
In a 318?
with iron heads?
Don't put your tools away........

Even the [email protected] is a hard sell in an iron-headed teener.
This cam is like the old Mopar 292/108 cam except with; slooow ramps, and an extra, useless, 20* of exhaust duration, and then advanced to where it will actually stay running, when you put it in gear.
But they stole all that intake duration from the compression stroke, so you're piston is over 2/3rds of the way up before the intake closes.
And they stole all the exhaust duration from the power stroke, opening the exhaust valve just as the piston is about half way down.
And they gave it 87* of overlap. That's a lotta overlap.
So what you end up with,( in the teener), in addition to the wicked idle, is a 7000plus rpm cam in a 5500 rpm engine that is down right sucked out until you hit 4000 or so,but doesn't really come alive until a week from Tuesday, cuz it's time to shift.
But that's Ok;
just put a long arm crank in it,aluminum heads,bore it to 4", and crank the pressure up.
And you'll be back in action.

Just don't take it out on the hiway as a 318,
unless you're towing a trailer with a big ole fuel tank on it.

But I know DWB is a smart fella, so he's gonna do all the oiling mods so he can wind his 318 out to 7000 or so. And he's gonna put some nice pistons in there and some aluminum heads so he can run the pressure up to say 190, and that is the foundation for a nice combo. The rest will be a dynomite killer cooling system, decent brakes, a 3500TC and some 3.91s or so, some big tires and a traction aider. Oh and the aformentioned trailer.

Oh wait, you're not putting it in there just for the sound are you?
In that case,lol
carry on. But
Don't put yur tools away

BTW, this is not hate towards the Thumpr. If I had an extra Barracuda, or two, I'd probably have one in one, just for the sound ...... cuz man does that Chevelle sound good.
 
Last edited:
OK...just to add more grist for the mill...do you have access to a Holley carb, say, a 600 or the proverbial 3310 750? (Now all you guys just hang on to the "But you're a Carter guy" comments for a sec...) He's changed everything except the carb and the cam. Holley's out-of-the-box seem to tolerate big cams better than Carter/Edelbrock's, so my thoughts would be to try a different brand carb and see what shakes out. Could be that 1406 just doesn't like Thumper cams.....

Just my $0.02
 
Carter/Edelbrock carbs respond better to throttle movements when a 4-hole spacer is under them. The higher the better.
 
Can't you just give your cam to any custom cam grinder and have them grind you exactly what you want? For $79?
 
I was pleased with the results of my thumper cam.

413 hp 430 ft lbs out of a stock stroke pump gas 360 with a dual plane intake.
 
65Val said:
OK...just to add more grist for the mill...do you have access to a Holley carb, say, a 600 or the proverbial 3310 750? (Now all you guys just hang on to the "But you're a Carter guy" comments for a sec...) He's changed everything except the carb and the cam. Holley's out-of-the-box seem to tolerate big cams better than Carter/Edelbrock's, so my thoughts would be to try a different brand carb and see what shakes out. Could be that 1406 just doesn't like Thumper cams.....

Just my $0.02
Click to expand...

That's because metering rod carburetors don't like it when they have low vacuum. They cannot decide where the metering rods need to be so they bounce them around due to low vacuum. Metering rod carburetors are very difficult to get right with larger camshafts.

I think changing the camshaft here is a mistake in trying to solve this problem. While the camshaft timing could be an issue, the camshaft itself is not.
 
doogievlg said:
I was pleased with the results of my thumper cam.

413 hp 430 ft lbs out of a stock stroke pump gas 360 with a dual plane intake.
Click to expand...
this is why I think there is something else going on other than the cam. if you're getting good results , then it's worth getting it right
 
doogievlg said:
I was pleased with the results of my thumper cam.

413 hp 430 ft lbs out of a stock stroke pump gas 360 with a dual plane intake.
Click to expand...

Most people are pleased that install them correctly.
 
AJ/FormS said:
In a 318?
with iron heads?
Don't put your tools away........

Even the [email protected] is a hard sell in an iron-headed teener.
This cam is like the old Mopar 292/108 cam except with; slooow ramps, and an extra, useless, 20* of exhaust duration, and then advanced to where it will actually stay running, when you put it in gear.
But they stole all that intake duration from the compression stroke, so you're piston is over 2/3rds of the way up before the intake closes.
And they stole all the exhaust duration from the power stroke, opening the exhaust valve just as the piston is about half way down.
And they gave it 87* of overlap. That's a lotta overlap.
So what you end up with,( in the teener), in addition to the wicked idle, is a 7000plus rpm cam in a 5500 rpm engine that is down right sucked out until you hit 4000 or so,but doesn't really come alive until a week from Tuesday, cuz it's time to shift.
But that's Ok;
just put a long arm crank in it,aluminum heads,bore it to 4", and crank the pressure up.
And you'll be back in action.

Just don't take it out on the hiway as a 318,
unless you're towing a trailer with a big ole fuel tank on it.

But I know DWB is a smart fella, so he's gonna do all the oiling mods so he can wind his 318 out to 7000 or so. And he's gonna put some nice pistons in there and some aluminum heads so he can run the pressure up to say 190, and that is the foundation for a nice combo. The rest will be a dynomite killer cooling system, decent brakes, a 3500TC and some 3.91s or so, some big tires and a traction aider. Oh and the aformentioned trailer.

Oh wait, you're not putting it in there just for the sound are you?
In that case,lol
carry on. But
Don't put yur tools away

BTW, this is not hate towards the Thumpr. If I had an extra Barracuda, or two, I'd probably have one in one, just for the sound ...... cuz man does that Chevelle sound good.
Click to expand...
saving for the heads and forged 4 inch crank....might get the cam re ground as well, still saving money over buying new roller cam!
 
You must log in or register to reply here.
-

Back
Top