I dont think the internals will be much of a resriction, just octane.
Honestly though, depending on how you option your turbo system the sky is the limit.
If we buy one to be the shop mule, I will be happy in the mid 450's to 500whp mark on pump gas.
Once the block shows what the limits are I suspect sleeving it with a darton MID kit + rods and pistons will allow big power. Like 800whp and above on racefuel.
Youtube a supra with a nice single. Then turn it up, close your eyes and imagine being behind the wheel of your 1LT....