Couldnt find pics of the engine 68 with the sub frame, but here`s one (the Verdoro car, was the object of talks here earlier its the one from the Mecum auction)) that may show part of the sub frame if you look carefully........but I did find engine pic of the 69 TA tribute car, engine from late model TA....he also has late model GTO interior , modified to fit. car is almost finished, he is still finishing up interior.
That's an LS1 (or maybe a LS6), not an LT1.
I'd stay away (far away) from LT1. The Opticrap (oops, I mean spark)and waterpumps are problematic and cost a small forture. And I know that from first hand experience - I owned a '93. Also, since they were only built '92-'96 Corvettes and '93-'97 F-body's any LT1-specific parts are getting harder to find and more expensive. One car mag recently did a rebuild on an LT1, and even admitted at the end of the article, they wouldn't bothered knowing what they know now (they picked up a cheap core trying to do a budget build).