454 build
 

building a gen V 454 motor has been balanced and bored .030 forged speed-pro dome pistons running a crane valve-train and the 420 cam heads a 117cc oval ports with 2.19/1.88 valves since I have switched to a mark IV style valvetrain I am using Mark IV push-rods(lenght is a little longer then the Mark V) comp ratio 8.79-1. I haven't started the motor but if i make the valves to tight will they hit the pistons and lock the motor?

Re: 454 build
 

The length of the push rod shouldn't matter with your lift. Your still adjusting the rocker arms on the mark IV set-up, were the length becomes a concern is how the rocker arm runs on the valve stem. If your running the stock style stamped steel rockers I wouldn't worry about it, if your running roller rockers you need to pay closer attention to how the rollor tip rides on the valve and get the correct valve geometery.

Re: 454 build
 

I would have checked the piston to valve clearance when I assembled the engine. :eek:

Re: 454 build
 

Cam timing has a distinct effect on valve to piston clearance. it should be checked when the cam timing is set and a weak checking spring can be used on the valves.

Re: 454 build
 

Today I pumped it up to full oil psi and adjusted the valves nothing hit installed the plugs everything seems to be ok now just have to wait for some shine and I will put it in

Re: 454 build
 

i wouldn't put an engine together without checking piston to valve clearance!!!!!