Coys C5 / Boss 338 wheel question

[CC69Rat]

I see a lot of trucks out there with Coys and Boss wheels, but I know .. there's a reason for that. They look really good on our year trucks. I like Intro Pentia too. I am just considering it right now, my rallys will need to do for a while.

I just have a question. My truck has the 73-87 cross member swap. Would I have the hub fit problems on the front rotors? Are the 71-72 different (OD of the hub) than 73-87 style? Would the front backspacing need to change, ex. tie rod differences, or anything? The PO has the factory spring with one turn cut out. I was thinking maybe ECE 2.5 drop spindles but I'm afraid that'd be too low with the big block. Your thoughts? Thanks.