Hydraulic roller or solid ?

[shoe4hire]

I am in the process of builing a motor at CNC performance and I have the choice of a Comp cam Hydraulic roller or a solid cam. I have started with them building it using the Comp Cams Hydraulic Mutha Thumper Part # 249-12-601-8 . Right now we are making 573 HP and 537 TQ on a engine dyno. They called me today and asked if I wanted to change to a solid roller with a .622 lift cam. They have dyno'd a similar engine today with the solid and make 636hp and 569 TQ.

I would love to have the extra power but I am worried and dependability and drivabilty. It is in a 1972 Camaro with a TKO 500 5 sp with 342 rear gears.

Any advise?

Thanks,

[shoe4hire]

The enigine is SBC 422 with 10.6/1 comp and AFR 210 heads.

[Lowend]

At .622 lift I'm worried about the lifespan of the valve springs

What durations are you looking at with the solid roller?

[Denvervet]

I am sure someone more expert then myself will chime in here....but...unless you plan on racing and "need" every last bit of power you can get I personally would just stick with the hydraulic. With more lift...it will be less tame for street driving and likely the torque and Hp rating are in a narrower rpm band than what you already have and may seem less powerfull until you get into that rpm range. My $.02 worth.

[shoe4hire]

I agree that I will loss some drivablity... But it is hard to pass up on 50HP and 50 tq.

I am leaning towards the hydrualic. I would love to have the extra power but I also don't want to worry about the valve train the whole time I am driving.

[68Formula]

The extra power sounds good, but where in the power curve does it come in? You want to look at area under the torque curve and decide how high you're going to rev this engine.

When you consider the valvetrain stress due to lift, the extra valvetrain and bottom end stress because you'll need to raise the rpm to use that peak power, and the sacrifice in driveability, I doubt it's worth it for bragging rights. Unless of course this is mostly a strip or road course car than it is a street car.

Oh, and let's not forget the TKO500 is rated to 500ft-lbs of torque. So the solid roller with more torque means more likely to damage the trans. Then let's talk about the rear. The 8.5" is strong from the factory, but will it hold up to that much torque or have you modified it to handle that much torque?

Consider the package.

[Vegas69]

Since it's a roller cam, I don't feel the adjustments will be as frequent as a flat tappet cam. If it was a big block I would say undoubtly to do it. A mechanical cam allows steeper ramps and more reliable high rpm power. Before I make up my mind, I have a few questions.

What is the intended purpose of the car?
What rear end gear do you have or plan to have?
What trans?

Keep in mind that opening and closing pressures are normally higher on a mechanical and you more than likely should rework your valve springs.

[shoe4hire]

The porpose of the car will be to cruise it on the street and do some track events IE DE Road coarse events. A few trips to drag strip but not set up for drag. Way too stiff.

The rear gear is 3.43

Trans is TKO 500
The power curve is very simial to the hydraulic cam every thing just moves up about 200-300 rpm.

Peak power is at 6400 with solid

Peak power is at 6200 with hydraulic

From 3500 RPM on the solid just makes about 40-50 more everywhere.

Its a tough call. It will require some more $ parts also.

The prior motor made right at 500 hp and the drivtrain held up great.

Just a tempting option.

Travis

[Vegas69]

If you run many road races, I'd go mechanical. You can still keep some drivability if you choose the right cam. Call up comp or isky and see what they recommend for both.

[shoe4hire]

My only fear now is if I go with the Solid roller then I may have trouble shifting my TKO 500. As they look to be only good for about 6500 RPM shifting. I would be willing to send it off to be worked on if I could make it better. But not sure about the ability to shift at 7k plus...

[Vegas69]

You don't have to pick a cam for 7000rpm.

[turner69camaro]

Go with the solid roller and put a good stud girdle on it and enjoy the power. That's the problem now days, everyone wants the most hp but dont want to sacrifice and do an annual valve adjustment that takes maybe an hour to do. Come on guys its worth the extra power to do. Personally I check my valve adjustment ebout every 3 months anyway.

[pitbull73]

yeah man go with the roller you will love the power band this cam has just get good girdles and u will b ok