I have and F20B I'm putting together and might I say that finding parts for this motor is very difficult.I have heard of B series rods fitting on these blocks? What I have so far is custom arias 85.5 piston with eagle h beam rods and a stock crank, unfortunately the crank is a bit small to hold the rods in so maybe I was wondering if I should switch out the rods, or go with a H22a4 crank.