I'm Building a 318 for a little more power in my 70 Barracuda.My question is this: do I have to change the pushrods in my stock 318 if I install a cam with more lift than the stock? It is an Hydraulic Cam.This valvetrain can't be adjusted? or it can? I ned help here.

 

I think you should be fine as long as everything measures out the same.{lifters, rockers, headgasket thickness}

It is possible to put shims under the shafts on the pedastals.

Worse comes to worse, aqssemble your motor with the intake off, you can see the pushrod compress the piston in the lifter slightly if everything is right. { the lifters that are on the base circle of the cam}

 

If the length is ok, I would replace them. Get a whole set from summit pretty cheap.
Also look for wear on the rockers where they contact the pushrod. can get them from autozone.

 

That's make sense to me, I think it will be no problem at all.By the way what kind of shims can be put under the shafts on the pedestals?Thanks for the help.

 

Good recomendation. I'm going to do that. Thanks

 

Sorry i didnt get back to ya fast, been busy. The shims I think are sold by Mancini but cant remember too well for sure. If you were bucks down you probably could make some out of aluminum.(.060 sheet??) The only purpose of using them would be to correct a valve train issue OR if you wanted to run your lifter plungers at the top of the plunger. (some people do this in conjunction with special lifters to try to control valve float at high rpm's) In the stock setup, as long as the plungers are compressed a bit , everything is ok. (you can actually run them halfway down the lifter body and it wouldn't make a difference) I think the factory spec is like 20-30 thousands.(maybe less)

 

Thank's for your help, it's not time yet to install the cam and the others things cause the shortblock and the heads are in the rebuilders shop but I see more clear now this task to do it by myself.