Hello All,
Just scribing some mental notes in hopes that they may be useful for someone else.
The LT4 will (obviously) require some way to adapt the motor mounts. The options I found are:
Dingo Glider Gen V LT Adjustable Conversion Swap Mounts
Dingo Double-D LT 1958-72 LT Gen V Adapter Plates
ICT Billet LT1 Engine Swap Bracket Conversion for Motor Mounts
Art Morrison LT1/LT4 Engine Mounts
32555765 LT1/4 Engine Poly Motor Mount
32555767 LT1/4 Engine Rubber Motor Mount
(see their catalog)
I ended up going with the non-sliding Dingo Double-D. The reason is that the sliding ones apparently have fitment issues with a low mounted, engine belt driven components on the Chevelle.
An updated shout out for Speedtech who produced a LT1 / LT4 engine mount:
https://lateral-g.net/forums/showthread.php4?t=55853