Also have another update which I wanted to start with a separate comment. Reached out to Trans Am's technical director about some questions I have and I've got a dedicated attack plan now.
The new LS1 will still retain a carburetor, but instead of building it to SGT rules we are going to build it to SCCA GTA's ruleset, which was essentially the original ASA spec engine from the early 2000's with modern off-the-shelf parts. The trade off will be horsepower, however TA's willing to write a new spec line for the chassis/engine combination once I get the car build and dyno'd that'll be a lighter weight than the current tube frame spec line. All those things considered, plus the significantly cheaper option of building a GTA spec engine makes this route the go-to route for me.
Also received an update to what body I'll be running. Trans Am wants all of their cars to maintain a showroom style look, so the Sportsman body is out. Really my only option with those requirements is the TA2 Camaro body, which I have to admit looks absolutely wicked. However, some of the former ASA chassis that underwent this conversion with the Gen 1 TA2 bodies ran into a problem with the greenhouse/halo and A pillars sticking out too much & being too tall to fit the Mustang/Camaro bodies. I'll have to get my car on the ground to take some cage measurements now that the body's off, but it should be around 51". Thankfully the current generation of TA2 body is 48-1/2" versus the 47" of the Gen 1 body, so I might be able to get lucky. I just really really really don't want to have to do the cage work that jh36 had to do this classic Camaro, as sweet as that is I don't have the time or consumable funds to tackle that.
Here's a great shot of the new body for those that live under a rock:
