Hi Guys!

Can anyone help me out with the valve train geometry calculation procedure for getting the correct push rod length for my 390? This is my first FE build and boy am I learning new things with this build, mainly that FE's are a little more expensive to build. I dont have adjustable rockers and I am running the Edelbrock Performer Plus 2106 cam which is a hydraulic cam and lifter kit. My heads were rebuilt by a machine shop and re-surfaced by .010. I purchased a comp cams adjustable push rod checker because I knew that I would be needing it but i just cant seem to find any concise info online on how to measure with non-adjustable rockers only adjustable. Can anyone help please? BTW this is a fresh rebuild so everything in the engine is brand new down to the lifters and cam. The lifters have not been installed or oiled yet. Thanks!

 

I recently swapped out my cam and replaced my .050" head gasket with a .020" steel gasket. I ended up getting adjustable pushrods, pricey at $200 from Summit but I wanted it as close to perfect as possible. I read different specs everywhere about how much the lifters should be compressed, from .050 to .200". I have a Lunati cam and lifters and they said .040-.080" if I can remember right and I set them as close to .060" as possible, again if I remember correctly. I really not comfortable that hydraulic lifters are self-adjusting in such a large range. Maybe call Edelbrock see what spec they recommend since they are the manufacturer.

 

Actually the Lunati specs were .020-.060" and I set them to .040". Install your cam and oil your lifters, install your push rod checker and rotate your engine to the half-way point between when the valve you are checking completely closes and starts to open. Start lengthening your rod checker until you feel the pushrod hit your lifter without compressing the lifter, lock it down and remove your rockershaft so you can remove your pushrod, measure the length of the pushrod and add how much lifter compression you want to that number. I would check it on a few different cylinders and find a happy medium. Long and tedious process. It would be quicker to throw in a set of adjustable push rods, lots of people don't seem to like them but I don't see whats wrong with them.

 

I'm in the same boat with my build, I have the same setup as yours. What size pushrod did you end up with if you don't mind me asking?