I'm replacing my 89 factory hyd roller cam with a new ZZ4 cam.

I'm looking to replace my pushrods also.

So here is the dumb question...

Since this cam has more lift than my old one, does that mean I need a different size pushrod? Or will the stock length one (whatever stock length is) be ok?

Any advice would be greatly appreciated.

Thanks!!!

 

Since the cam base circle is probably changing, and the head height will likely be different, you will have to loosely assemble a head to the deck, install the cam and a pair of lifters, and mock up one pair of valves to check for correct push rod length. Just changing heads with the stock cam can require different length rods, and changing the cam with stock heads can require different length rods. Even changing the rockers can require different push rods. Given the number of variables you have introduced, you really need to assemble one pair of valves and check rocker geometry for yourself.

 

Thanks for the reply, Vader!

I see your point about how many variables there are.

Once I have the heads bolted up and the lifters in place, how will I know how much longer of a pushrod to get?

I'm looking at a catalog that has numerous sizes and they are all very close to each other in length.

If my stock ones are too short, I hate to spend alot of money buying X different sets of pushrods and using trial-and-error to get the right length.

Sorry to ask so many questions, but I'm new to heads/cam upgrading.

Thanks again