Keep it as far back as you can. I found that the problems comes in the front. Remember the water pump sits much lower on the 350 SB, in order to get air through the radiator you will need a shroud. I could have put mine an inch or so farther back and eliminated the relocation of the side mounts on the radiator, triming the rad support etc., I took it forward and down, used a 17" engine driven blade and custom built cool shroud. My a/c condenser and trans oil cooler are in front, easier fab with more room. See here
http://community.webshots.com/user/zeker6
Still not on the road yet but it seems to pull lots of air. Zeke


The Amish Connection
51 Chevy 1/2 ton 5 window,Vortec hotrod, no horse