what lenghts push rods should i run. stock bottom end,stage 1 prc heads, with the ms4 cam. will the 7.4's work

 

Moving to internal section.

Your bottom end will have no difference in deciding on your pushrod length. I am not sure if the MS4 has a smaller or larger basecircle, but I think it is gonna be either a 7.400 or 7.350 Depending on what your heads are milled and the gaskets you are running. I would try searching under MS4 on the site and see what you can find. I know this has been asked numerous times before.