I recently bought a create motor from gm, basically the stock short block that belongs in my 89' IROC. I put a set of Edlebrock performer centerbolts on and a crane compucam. I am pretty much done with it but I am concerned about getting the proper piston to valve clearence. Please help me figure this out.
thanks.

 

There should be at least .100" piston to valve clearance.

 

Ok but how can I check what the piston to valve clearence is?

 

Put some putty on the pistons and turn the crank with the heads on. .100" is the least amount of clearance you can have.

 

Is it possible to figure it out without having to take the heads off. Like with an equation or something.

 

Using the putty method also requires using soild lifters while checking clearances.

There is no "easy" way to calculate or check clearance. Too many cam profiles and piston styles. Advancing or retarding a cam installation can change the clearance also.

What kind of pistons are in the engine? How much lift and duration is the cam? Stock 1.5 rocker ratio? How much deck height is there?

 

Since you said "Compucam", even the largest compucam won't ever come close to hitting. I'd bet $5000 on it.

 

Well the piston are just stock 9.5:1 compression, there not domed or nothing. The cam is 194 intake 204 exhaust, .407" intake and .429" exhaust. My major concern was the heads. Jegs says you must have a pushrod .1 longer than stock when useing stock rockers. Originally I was going to use the stock ones but now I am using crane fully rollerized rocker ment for centerbolt valve covers. So do you think I will have a problem. Oh yeah and I used a pushrod checker and it came up saying I needed a pushrod 1/16" shorter than stock. Can I just use a stock size or should I order the correct size. The cam was actually the smallest one that is made for my application because I couldn' afford to sway torque converter. Thanks for your help

 

Since hydraulic lifters have zero lash and around .030" preload, pushrod length has nothing to do with lift. It just changes valve train geometry. You should be safe to use stock length pushrods. With lift that low, stock pistons and no block decking, there's no chance of having a valve hit a piston during normal operation.