[Kris Thompson]

i have a sbc bored .60 over with flat top pistons and a texaes speed ms4 cam with a .649 .609 lift solid roller.. my question is can i run 305 double hump heads they have 2.02 valves my cam specs say to use shorter pushrods 7.425 length im not sure what stock is but they are shorter then the ones i pulled out of motor. i just dont want valves hitting pistons but i would like to have the compression and valves from those heads.

[68NovaSS]

I've never heard of any 305 heads that are true "double hump", or any with 2.02 valves for that matter, 305's only have a bore of 3.736, they would have had major cylinder clearance and shrouding issues with 2.02 valves.

You wouldn't have valves hitting pistons with longer pushrods. The cam lift and duration are what the are, and that is what will dictate whether they hit pistons, long/short pushrods will only change the valve train geometry, unless you had them adjusted too tight, and that can happen with any rod length. You would have other major issues if that were the case.

[cobalt327]

Originally Posted by Kris Thompson

i have a sbc bored .60 over with flat top pistons and a texaes speed ms4 cam with a .649 .609 lift solid roller.. my question is can i run 305 double hump heads they have 2.02 valves my cam specs say to use shorter pushrods 7.425 length im not sure what stock is but they are shorter then the ones i pulled out of motor. i just dont want valves hitting pistons but i would like to have the compression and valves from those heads.

Solid roller p-rods are going to be a lot shorter than stock SBC (~7.8"). Exactly how long depends on a lot of things. If you know who's roller lifters you are using you can get close enough to the right length to start the geometry measurements to get the exact length needed.

HERE is a list of valve train points to check.

I don't think those 305 heads- regardless of how much porting has been done- will ever support a solid roller cam w/that kind of lift and duration. The only thing they have going for them is a small chamber, but even they won't be so small once the chambers are unshrouded to let the 2.02" x 1.60" valves breath. The ports are just too small to flow at the lifts and RPM that cam is going to need to make power like it should. The engine will run, but it will not be anywhere near where it should be, power-wise.

[BOBCRMAN@aol.com]

Seen them before. Premium fuel, nasty sounding, turd. Then the guy puts one of them in a VAN of all things.. Complains that the power brakes and the trans don't work right, has no power.. Wanted my shop to correct the problem!!!