So, it looks like one could go with the 347, and the 331, if they can use a 4bbl intake, and figure out how to use either hipo or 351W exhaust manifolds.
I really like the crate motor idea, too. Those motors would need to use the HiPo/351W exhaust manifolds, too. Wouldn't you also need to use one of those retro-looking timing covers for the later 5.0 motors?? (available from Cal Pony Cars?)
The '68 Shelby GT-350 HP rating was 250 (torque- 310@3200
The GT-500 HP was 360 (torque--459 @ 3,200).
The 347 ratings aren't in front of me, but isn't it about 400hp? With lots of torque? That would make a GT/CS "as fast" if not more than a stock 1968 Shelby.
I would like someday, to hear folks say, "hey, there's one of those GT/California Specials....those are fast cars. As fast or faster than a '68 Shelby". That's a reputation that we can live with.
thanks everyone for your help. I hope that his will inspire others to look into doing this. I'll research the part numbers to actually do this--for the book.
Paul N.