How much horsepower would you estimate?

I would estimate that your easily pushing 550hp at the flywheel which is stout and awesome.. I always loved LTx and TPI motors.. but to the point the trickflow top end kit is truely meant for a 383 and 396 lt1 strokers it performs much mutter than a stock 350 lt1, LT4 intake manifolds flow like crazy, you now have a cold air lid and headers which you didn't have before your seeing some nice power