OK, this much I know...
 

An F-body LS1 will fit far better than a 'Vette LS1.

But, what about a pull from a GTO?

http://cgi.ebay.com/ebaymotors/ws/eB...982192123&rd=1

Can't say I've seen anyone try one yet. The issue with the vette motors not fitting is the oilpan and the accessories. If nothing else you should be able to swap in the f-body stuff if it didn't fit.

I wouldn't mind getting it... only 4000 miles on it, and aren't they rated at 375/375?

Something like that. It's only relative if you leave it stock though. If you plan on adding heads or a cam to it, then the stock output is pretty meaningless.

350 hp, 365 ft. lb.

That's good enough for me.