I have a HEMI that used to be a blower motor and I need to put a new crank and rods in it. It has a flawless set of Venolia pistons that I would like to keep but they have a 1.5 pin height so they come up real short. I can either go 4.15 crank with a 6.86 rod or option B is a 4.25 crank with a 6.76 rod and I can fine tune compression "10:1" with the head gasket thickness from there. My question is will the 4.25 crank work with a 6.76 rod or will the pistons hit the counter weights?

I just picked up an old race Hemi myself. It already has a 4.25 crank. From what I modeled up in excel I think a 1.5ch piston, 7.1" rod and 4.35 crank will work out pretty good. The longer rod drives towards better rod angle. If my spread sheet is close to being right, you should end up around 10.8:1 with a lot of assumptions for dome volume, chamber volume and gasket thickness.


The issue I have is that it looks like my pistons have a CH of 1.34" which is real short. I am trying to decide if I want to figure out how to use that (I haven't found any 7.2" rods) or go with new rods and pistons.

Those combinations would work but the problem I will have is compression. These pistons have huge 148 cc domes and with that stoke it would be 23:1. To use these pistons I have to keep them from coming all the way up to the top. They need to be about .280 under deck height at TDC.