what is the number one power adding thing that can be done to TPI?

 

What are the constraints?

If you're talking about a stock L98, I'd say the heads.

 

Supercharger?
Nitrous?

 

sorry, let me be more specific. Short of forced induction what is the best thing to do to add power?

 

Assuming the stock 5.0 Liter or 5.7 Liter is in good shape and that budget is not a problem I would suggest the following in this order:

1.K&N air filter
2.Headers
3.Removed catalytic converters if local laws permit and improved exhaust system
4.Port Plenum, Runners and intake manifold or
5.Improved intake system
6.Adjustable fuel pressure regulator in combination with 4 or 5 above
7.Ford Motor Racing SVO fuel injectors in combination with 6 above
8.Heads
9.Camshaft
10.Rocker arms coordinated with the camshaft
11. Performance PROM chip

 

With out getting into the motor I'd say exhaust(headers,catback).
Getting into the motor cam or heads.