Stocker Cam Lobe Profile ?

[Alan Roehrich]

Originally Posted by Aubrey N Bruneau

I knew you guys would like this subject !

Yes, short stroke... VERY quick revving.
Phil, it IS good to 7000..... it's the 7400 that it saw on my fastest qualifying run... which BTW, seems to be a pattern. The higher RPM range DEFINITELY had the car going better speed and ET ( though 7400 was NOT deliberate ! ).

If I shorten duration, and / or advance the cam, I'll have to rely on this thing becoming a mid-range torque monster, in order to achieve that elusive 125 MPH. It won't do it.
Paul, when we went back to back on the dyno, and the cam was retarded 4 degrees, the engine torque curve moved up, but didn't change numbers. Peak HP jump by 18, and the engine hung at peak HP through 6700 RPM. It doesn't lay down... and I LIKE THAT ! ! ! !

My cam may be a little "out there" already, Alan ?
264 / 272 @ .050", on a 108.
I've contacted Ferrea a few times about making valves for me.... they flat out REFUSE.
2.20" / 1.735", but about .100" / .125" shorter than BBC.
Spring installed height is also much shorter than BBC... it's basically the same as small block. My current spring was Comp's strongest beehive, with a 11 gram tool steel retainer. Shimmed stffer on the intake, the spring was almost stacked.

At this point now, I'm willing to give up 10 potential HP, by using a softer ramp intake lobe. Due to recurring disasters, this engine's cylinders are right at ..074"- 075" over.
In addition to this, due to multiple repairs, and grinding that has gone on with these heads, they would no longer pass tech. I have another pair of virgin large port castings... actually they are the "better" 583 's. I don't want to take chances with the them.

Aubrey, I can get the valves made, and you can actually use the extra 0.100" installed height. I can have them made from the same blanks my valves are made from. Do not worry about getting the valve stem shortened. You adjust for the longer installed height by using a longer pushrod and a longer rocker stud, if necessary.

What is the largest diameter valve spring you can fit on the head without cutting the spring seat? If you can get a 1.540" or 1.550", that's ideal, if not, we can make something work.

What is your current installed height? You need at least 1.850 or so, if you have 1.750", which is small block height, then 0.100" to 0.200" longer valves would work much better. Between 1.900" and 2.050" is ideal. The right retainer and/or keepers can make that happen.

I'm not at all a fan of the beehive valvesprings for what you're doing. There are regular valvesprings that are a known quantity, we KNOW they'll work with the lobes you need, and with the valves you need, and they'll work at 8000 RPM.

By the way, with the modern lobes used on the really fast 427 Chevy Stock Eliminator engines, that cam is huge, no one I know running a 427/425 runs nearly that much cam, and they're turning 1000 RPM more than you, and making more HP. If you need more RPM, you can spread the LSA out to 109, or even 110, that will let it carry further without nosing over.