LS1 Swap in 74 Nova
That should get you pretty far. Stock rods?
With trans, you don't have a lot of options with a turbo. T56 or T6060 for direct bolt up newer style transmissions. There are adapters to use the Nissan 370z transmission but in the long run the cost is similar to the T56. The older Super T10 and Muncie M20 can be made to bolt up and work decent with a turbo if you find the right models. Might be cheaper than the T56 but you lose the double overdrives.

