Turbo Buick Forums banner

How to determine required push rod length?

1.2K views 5 replies 6 participants last post by  87bigcut  
#1 ·
My heads needed .005 taken off to true them up and my block was previously decked but I don't know by how much... I'm guessing it probably took .005 also... will I need shorter pushrods now? if so I have no idea how to calculate pushrod length so I need some advice on how to do it.

thanks
 
#2 ·
On paper you could do that kind of math and find out the length of pushrods you need. (That's also with the same compressed thickness with your headgaskets, same exact base circle as stock, etc.......)


In the real world, the only way to make sure that you've got the exact "right" length is to assemble, measure, order, install, measure, and then hope they're right the first time.

Luckly you do have a little SWAG to deal with and you don't have to be that exact.
 
#4 ·
easiest way to do it is to use an adjustable pushrod...assemble everything, set the pushrod to zero preload and measure the rod...add .030" to the length...

or, compare to the stock length rod and shim the rockershaft to make up the difference.
 
#6 ·
I cut up and old pushrod and welded a nut on each end after taking out about a half inch. After setting to zero preload and measuring, adding .030 I came out with an average of about 8.625 I think. Got them coming from crower.

Joe