Cam Choice, roller or flat?

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comoxian

comoxian

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Hey all,

Seems that Comp Cams is out of blanks to build me a roller cam, as I wanted to retain the stock roller lifters that were in the 360. They may have some late July or August. I didn't want to wait that long.

I was going to use their Thumpr hydraulic roller.

Specs:
Dur - 283/303
Lift - 513/498
RPM - 1900-5600

Seeing as it wasn't available, the supplier got us what they thought was close, in a flat tappet. I don't think it's close, but I'm no expert.

It's their Mutha Thumpr hydraulic flat tappet.

Specs:
Dur - 287/304
Lift - 497/483
RPM - 2200-6100

Searching thru Summit, I found what I think they meant to send. It's stock number is very close to the one above.

It's their Big Mutha Thumpr hydraulic flat tappet.

Specs:
Dur - 295/312
Lift - 507/494
RPM - 2500-6400

Is there a big difference between the three of them?

I have a fresh 408, with 9.8-1 comp (10.5 maybe, can't recall), 3.91 rear end. I'm shooting for around 450hp, but 500 would sure be nice.

Is there anything else that I should consider?

I'd really like to get this thing running this month. =P~

Thanks for your replies.
 
I have a Comp Cams solid roller Grind#CRS 4006B/4013B R.110.0 it has a .631 lift,@106.0 [email protected] is 252/258lobe lift is int. .4210 ext. .4210.This is in my 408(410)this weekend was my first time running at the track,ran a best of 11.32@120mph 60 ft was 1.65.I was pleased with my first time out.Now for some tweeking!LOL.Need 10,s:clock::cheers:
 
I will always use a roller cam.
After seeing how many flat tappet cams fail I would never do it.
 
My builder used a Comp solid flat tappet in my 414 stroker. As long as you use break in oil with zinc and proper engine break-in you should be okay. That's the difference with today's oil. If you look at most stroker builds with a decent cam & top end they make 450hp easy. Just my .02.
 
POS Dakota said:
I will always use a roller cam.
After seeing how many flat tappet cams fail I would never do it.
Click to expand...

X2...been there, done that, got the tee shirt... rebuilt my motor last year thanks to piece-O-crap flat tappet cam. Roller is the only way to go, IMHO.

BTW, why not check with Bullet cams? I bet they would make you a nice custom grind.
http://www.bulletcams.com/
 
What head are you running? ported, unported?
 
I was going to suggest Bullet. I dont think any of the cams from Comp you mention will come near to 500hp. Might not make 450 depending on the heads.
 
I wouldn't settle just because Comp can't supply you with what you want. There are other cam manufacturers out there. Pick one from those other guys.

Chuck
 
flyfish said:
What head are you running? ported, unported?
Click to expand...

Thanks for the help guys. This is my first build.

I have the Eddy RPM heads, so far unported. My speed shop didn't figure they needed any work done. I have an Eddy RPM Air-Gap intake, also, if that makes any difference.

I'll check into the other suppliers too.

I can still use the Comp Cam rocker assembly, regardless of cam choice, correct?

Guess it's not gonna be built in time for Mopar Madness in July. Oh, well.
 
Roller cams are nice, but cost way more than any flat tappet around. Also, retrofiting one for an non-roller LA block is a PITA from what Ive heard. IMO, I would say to run a solid flat tappet, but use Rotella 15-40 diesel oil, because of the high zinc content. Diesels dont have as strict smog tests as gasoline engines, which means that the oils they use arnt limited to what good stuff they put in it.
 
And yes, the comp rockers will fit regardless of what brand cam you use.
 
................Rotella does not have the high zinc every1 thinks it has as its been reformulated more than a year ago...............kim.......
 
Rockerdude said:
Roller cams are nice, but cost way more than any flat tappet around. Also, retrofiting one for an non-roller LA block is a PITA from what Ive heard. IMO, I would say to run a solid flat tappet, but use Rotella 15-40 diesel oil, because of the high zinc content. Diesels dont have as strict smog tests as gasoline engines, which means that the oils they use arnt limited to what good stuff they put in it.
Click to expand...

My block is a roller LA, that's why I was wanting to keep the stock roller lifters, I was told that it was the preferable way to go.

But I'm no expert. Just wanna go fast. =P~
 
comoxian said:
My block is a roller LA, that's why I was wanting to keep the stock roller lifters, I was told that it was the preferable way to go.

But I'm no expert. Just wanna go fast. =P~
Click to expand...

Oh, well in that case definatly go roller! No good taking a step backwards..
 
oldkimmer said:
................Rotella does not have the high zinc every1 thinks it has as its been reformulated more than a year ago...............kim.......
Click to expand...

This is the first Ive heard of this... Where did you learn that it was reformulated?
 
Definitely stay roller. Easy to deal with, more power too.

Bullet cams does a great job on cams, not so much on web design.

Steve
 
I heard that on the pre-magnum roller blocks, its as easy as just replacing the roller stuff with flat tappet. Idk for sure if its true or not.
 
Mark, so your 360 is pre magnum with oem. hyd. rollers ? You "could" convert them to mech.,(gut and install sleeve under the push rod cup). Doug Herbert has 5 different mech. rollers and retrofit solid roller lifters. Regrinding the stock roller, will be too mild, for your application. Good Luck, ateam.
 
I have NEVER had a Flat Tappet Cam go Flat. I almost think something else causes flattening of these cams which gives them a bad name for no reason. Using the Wrong Oil, , Wrong spring Pressures for application, Valves adjusted improperly, lash not set correct with Hyd, Old lifters on new cam, binding of springs etc with too big cam not enough machine work? Just my02 cents.
 
Mad Dart said:
I have NEVER had a Flat Tappet Cam go Flat. I almost think something else causes flattening of these cams which gives them a bad name for no reason. Using the Wrong Oil, , Wrong spring Pressures for application, Valves adjusted improperly, lash not set correct with Hyd, Old lifters on new cam, binding of springs etc with too big cam not enough machine work? Just my02 cents.
Click to expand...

Same here, nothing against roller cams but I'd prefer a good solid flat tapped in my motor.(being a non-roller block) money better spent else where.
 
Bullet's website is perfect for designing a custom cam. That's pretty much all they sell. If you are not quite as into the process, call and talk to them. In terms of possibility and quality they are heads and shoulders over Comp. The guy that helped Comp with the Extreme Energy line and Lunati's VooDoo line is one of thier lobe developers. Ultra-Dyne Harold. Not chesp, but very, very good product. If your shop said the heads are fine without knowing what cam you're running (and after thinking they were going to use the ones you mention...) I would try to find a shop that says you need at least to upgrade your valve springs. I ended up scoring a nice leftover Crane when I was doing a build last winter. The factory hydraulic rollers are better parts than the aftermarket stuff. I used some replacements from PAW.
 
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