More Sideways than forward..

spacers are 1/2 mild steel with hole drilled in center for bolt. If you want a pic pm me a e-mail and I will send you a pic of the spacers. 383 is not that hard to get in an a-body, 440 is much more challenging. Overdrive I hope is a cast iron case ? version. If you plan on slicks be warned small bolt pattern 8 3/4 axles and slicks end up sounding like a little kids vacuum popper lol. Make sure you have frame connectors and a drive shaft loop. Steering column auto or stick does not matter clearance is what you are after. If you look there is a small screw holding the collar in place. you are simply moving the bushing up against the firewall as far as possible to gain clearance. Make sure you weld in the plate for the Z bar stud as the sheetmetal will not support it and the sheetmetal will tear. It goes behind drivers side wheel in the wheel well. the hole is there but the plate was only put in stick cars.
http://www.brewersperformance.com/proddetail.asp?prod=FB676