I have a 74 corvette 350 with a hydraulic cam. I have a pair of these Pro Topline heads http://www.protopline.com/2236494906.asp

I bolted on one of the heads, then started to bolt on the rocker arms. At this point, we noticed that the pushrods were too short, probably by about 1/2". So first I called the guy I got the heads from, and asked him what length pushrods to use. He told me to use the 7.8" pushrods, which is what I have. After a bit of research, I realized the heads are designed for a newer motor with a roller cam and lifters. My first thought was to just use longer pushrods, but I wanted to make sure there weren't any other problems. Does anyone know whether or not I can use these heads with my motor? If so, is it just a matter of longer pushrods, or is there more to it?

 

You should be able to use standard length pushrods with the heads. I believe the roller lifters are a bit taller than flat tappet ones. 96 + vehicles would have roller lifters which could be why those were recommended. I'm not 100% sure on this, so hopefully someone can confirm.

 

Those are the Vortec replacement heads. As far as bolting to the block, there is no difference. As far as the differences between heads used with roller cams versus flat tappets, there really are none. The only differences are the pushrod lenght (which has no effect on the heads being designed for one engine or another) and the method used to center the rocker tip to the valve.

You will need a new intake with those heads.

By the way, pushrod length checking tools do exist.

 

I was my original thought to just use longer pushrods, but I wasn't sure if there were any internal changes like the reverse flow cooling on ls1 motors. I bought a pushrod checker, but I just wanted to make sure that the pushrod length is the only problem that I would run into. When I purchased the heads, I also bought an intake to match. Thanks for your help.

 

be sure and check for clearance issues where the pushrod goes through the head if you swap to a bigger diameter.....btw what length did you come up with...just curious

 

what diameter pushrods should i use? i honestly won't get a chance to check the length for another week or two. i'll let you know when i find out.