If I was you and know what I know now I would build the 400 with a 4.25 stroke with BB chevy rod sizes, use the longest rod length your comfortable with I have one low deck 400 block with 4.300 stroke Chinese crank, pump gas motor that is in the car now tat has 6.8 long CAT H beam Chevy rods in it. I have since built another 400 block with a 4.25 stroke Ohoi Crankshaft Company Hemi crank cut down to fit the low deck mains, Chevy rods cut the counter balancers too clear the block. It has 6.7 long RPM rods in it, I have not ran or dynoed that motor yet so on numbers on it. The pump gas motor made 718 HP and 744 ft. lbs on Oregon pump gas several years ago with a set of Eddy RPM CNC heads done by MCH and a low deck six pak, the new motor will make more with the same Eddy heads and more compression for E85