I'm building a 400 for my 1970 Chevelle Malibu and at first I was going to put a Comp Hydraulic roller camshaft with .525"/.525" lift to go with the vortec heads I purchased. But after looking at the cost of the lifters and cam I began looking at just a plain hydraulic tappet cam and lifter set from Comp with the same exact lift for half the price. Would there be much of a performance difference between the two cams or should I just bite the bullet?

- T-Pat

I have no way to compare before and after since I changed many things at the same time, but I went to a hyd roller and love it.

I'm running a 231/239 @ .050, .535/.550 lift voodoo cam. With 1.6 rockers on the intake side I'm at .550/.550. Very rumpity and good street manners.

You can get away with a bigger cam, but with a hyd roller it is important to have good heads and upgraded valvesprings.

the difference in power between a roller and flat-tappet is night n day.. i wouldn't use a hydraulic roller, the lifters can't hold up to the high spring pressure required by the roller..

The roller cam, will make a bit more horsepower just because of the frictional advantages, and roller cams have more agressive ramps built into the cam. The thing about hydraulic rollers is the added weight to the valve train pieces. Hydraulic rollers seem to run into valve float issues over 6000 rpms. It whatever you budget can afford.

Dave

I figure my heads should be fine. They have been CNC'd and port matched and had GM performance springs put on them set up for .530" lift hyd. roller cam.

i wouldn't use a hydraulic roller, the lifters can't hold up to the high spring pressure required by the roller..

Don't let every OEM engine manufacturer for the last 15 years or so know this!! :confused:

If you aren't building a pure strip car, shifting at over 6000 isn't a must. Mine shifts at 6200 presently, I actually need to move my shift points up because the thing is still building up quite a head of steam. No traction at all on the 1-2 shift at WOT. This is with 3.31 gears and a posi!

The cam you are looking at is it the hot cam kit from GM?

Dave

The roller cam, will make a bit more horsepower just because of the frictional advantages, and roller cams have more agressive ramps built into the cam. The thing about hydraulic rollers is the added weight to the valve train pieces. Hydraulic rollers seem to run into valve float issues over 6000 rpms. It whatever you budget can afford.

Dave

Yea, I heard a lot of people tell me that. I don't think I have to worry too much about that though. This is going to be primarily a street driven car.

The cam you are looking at is it the hot cam kit from GM?

Dave

No, but it is almost identical. I don't have a late model block that that cam would work on. Mine is just an old 4 bolt main 400.

This is going to be primarily a street driven car.

You always see that statement. But does making that statement mean it will never have a foot in it? That it will be driven like grandma on
Sunday morning?

The first time you float the valves and you hear KABOOM, you are going to tell yourself, it was supposed to be a street driven car driven like grandma.....


:thumbsup:

Don't let every OEM engine manufacturer for the last 15 years or so know this!! you sure you wanna play with me.........we're not talking OEM, we're talking about a 400SBC with an aggressive retro-fit roller that will most likely see rpm's of 6000 plus on a regular basis, i think you know what happens when there isn't enough spring pressure to keep the lifter in contact with the camshaft and/or the valves begin to float and very expensive noise eminate from under the hood.. the spring pressure required to keep that from happening is very hard on the hydraulic roller lifter itself and they known to fail under the circumstances.. if we wre talking OEM and miold cruisers that don't more than 5500rpm then yes a hydraulic roller is fine. now before you spout off another smarta$$ comment to me think 2 x about what your saying..

the difference in power between a roller and flat-tappet is night n day.. i wouldn't use a hydraulic roller, the lifters can't hold up to the high spring pressure required by the roller..

Small block valvetrain,, not as heavy as big block. LJ

you sure you wanna play with me.........we're not talking OEM, we're talking about a 400SBC with an aggressive retro-fit roller that will most likely see rpm's of 6000 plus on a regular basis, i think you know what happens when there isn't enough spring pressure to keep the lifter in contact with the camshaft and/or the valves begin to float and very expensive noise eminate from under the hood.. the spring pressure required to keep that from happening is very hard on the hydraulic roller lifter itself and they known to fail under the circumstances.. if we wre talking OEM and miold cruisers that don't more than 5500rpm then yes a hydraulic roller is fine. now before you spout off another smarta$$ comment to me think 2 x about what your saying..

Then I'll tell you, first hand experience - I use hyd rollers, I spin it OVER 6000 RPMs.

Valve float is bad no matter what kind of lifter you have, I don't see how it makes a difference what kind of lifter you're running. People that want to rev to the moon probably aren't looking at hyd lifters anyway.



You made a very general statement, I had no idea I was supposed to imply so much by it.

I almost forgot to add a :rolleyes:

So all in all, is there a lot of power loss by going with a hyd. tappet instead of a hyd. roller? lol

hyd roller will make more power simply for the fact you have more lobe area under the curve. This is why Ford came out with the hdy roller cam in the little 302 back in the '80's that gave chevy Z28's fits.

Longevity. Because of EPA rules and the fact the OEM's don't use flat tappets in production cars anymore the lifter of today is not the same as it was. A solid flat tappet cam and lifters could wear out in as little as 20K miles. A hyd roller willl keep on ticking.

now before you spout off another smarta$$ comment to me think 2 x about what your saying..
:boxing:
I almost forgot to add a :rolleyes:
Too funny, you guys are killing me....:Dl:)

point taken, i was thinking more along the lines of a heavier BBC valvetrain:clonk:

my friend killed a flat tappet in a 70 gsx in 100 miles. stock engine 455 stage 1 stick shift.