Drivetrain Power Loss -- Too much!

[seattle67]

Hi All,

I finally finished my 67 Camaro pro touring project and recently went through a few tuning sessions on a Mustang chasis dyno. I had the motor dynoed after assembly (modified zz502 w/ Edelbrock ProFlo RPM EFI) and came out with 598 HP @ 5500 and 604 ft/lbs @ 5000 at the crank. My best Mustang chasis dyno HP numbers were in the mid 430's at the wheels .. that's 27-29% powertrain loss (ugh!!)

FYI, I'm running a Tremec TKO600 (5 spd OD) and a DSE narrowed Ford 9" (Moser 31 spline axles with a Detroit True Trac posi), headers with 2 1/8" primaries flowing into dual 3" Spintech exhaust. With this combination, I do NOT believe that I should be losing this much power, but I do understand that things like ambient air temp can account for approx. 30 wheel hp or so, but that doesn't explain the delta.

Has anyone run into simlar hp/tq loss with any of these powertrain components?