1950 chevy 3100 open drive install question

[butterboy]

Hey guys question for ya.
I am installing a open drive rearend in my 1950 chevy pickup.
the rear is a 1/2 chevy six bolt rearend. I got 3.5 inch blocks to lower it and took out 3 leafs. Now my question : I drilled the axle side of the block on center and pressed in a pin. On the other side(spring side) I drilled a hole 1-1/2 from center to help with centering the wheels in the fenders. I mocked everthing up and my wheels are still to far forward. What are my options to correct this? Anybody know how much more I need to move the axle back?
Thanks guys!