mj88stang

what is the deal when installing aftermarket roller rockers, do you need shims, if so for what,what about pushrods, do you have to change length when adding roller rockers? say i am adding 1.6 pedestal mount rockers to 88 5.0 HO, am i going to need shims and different length push rods?

myshifter

pushrods, no. shims if you want to play with lifter preload. It's a good learning experience

BCP

I agree.

mj88stang

what am i gonna learn?

BCP

how to adjust the rocker height to properly pre load the pushrod. Since pedestal mount rockers arent naturally adjustble due to design unlike a stud mount rocker, you cant adjust them to pre load the rocker properly. Shimming them helps accomplish this.

usually the only rockers that need shims are the 1.7 ratio.

myshifter

well if you ever build something a little more radical and run into different issues, such as the heads were decked 10 thou, the deck was milled 15 thou, you need to be able to compensate for these things. Say you got 50thou lifter preload now on a stock motor, but the heads and deck combined are an extra 25 thou, now your running 75 thou lifter preload, so I would run a 25thou shim and lessen the peload. Lots of things to deal with when building an engine, its not like legos or paint by numbers