Drivetrain Power Loss -- Too much!

[Steve Chryssos]

Agreed. That sounds like a big drop. Dyno'd a 400 small block recently.
575HP on W2W's engine dyno, then 460 rear wheel on a Dynojet. That's 20% with a 4L80E and a very restrictive (had to be super quiet) 2.5" exhaust. And 4L80E's have a reputation for high parasitic loss. That reputation is unfounded, obviously. It's all in the converter. But I'd like to see 15% for your stick application. So 500 to 510 rear wheel. That is if your engine dyno runs were made with all accessories in place and your headers--not dyno headers. Otherwise, there might easily be 30HP hiding in your accessories and another 40 in your exhaust and tune. Your 598 ain't 598.

If the engine dyno numbers are net, then the easiest test is to make another run uncorked. If you find the lost power hiding in your exhaust, then re-connect and start playing with your fuel injection map. Hopefully, the Edelbrock system can be fine tuned to regain some of the lost power.

Good luck