Helping friend w/'74 Blazer engine swap

[Billla]

Folks, I'm primarily active on the pickup side of the board but a buddy has asked me to help him "recover" from a bad engine swap. Basically, a "friend" of his traded him swapping in a butchered "Corvette" 327 for the stock 454 in his '74 automatic Blazer. Needless to say, it's a mess - welded up PS bracketry, etc. We have the 327 pulled to see what he can get out of it, but he wants to put a mild 454 back in. We're starting to plan that engine build now, seeking a rebuildable core.

I'm completely new to Blazers, so I'd appreciate some broad guidance as well as a few specific answers:

• Are Blazers the same as P\U in requiring the proper "towers" for BBC vs. SBC? If so, are the BBC towers available?
• I ass*u*me that a different bellhousing/flywheel/starter is required (TH350)?
• ALL the bracketry for the alt and PS are missing - is this stuff avail aftermarket either stock or upgraded (March, etc.)
• Does any have some good engine bay pictures with a 454 in a 1974 Blazer?
• Anything else I should be thinking/worried about?

Thanks, folks. I'm sure I'll have a ton of questions, so I'll thank you in advance for your help!