bartamos...the engine is a '95 out of a Buick Roadmaster. I just finished installing a bolt-in crossmember from Speedway. The IFS is suppose to deliver 7/3. The only thing north of the firewall are the frame rails and now the crossmember. I purchased a set of SBC engine mounts and have them loosely attached. Once I get the IFS installed, I'll bring my engine and tranny out of storage and start the mock-up. Work around right now is as easy as it will ever get!
I've seen photos of LT1's with headers. I would be surprised if they were all of the '70-'72 vintage but I'm only guessing. I hope you're right that previous bolters who have done this will respond.

Thanks John Milliman for interpreting my original post with an open mind.