[Tom-In-Ohio]

Comparing engine dyno with chassis dyno results .....

Most engine dyno shops use large diameter, long tube racing headers in their set-up. The sidepipes/mufflers do not enter the picture. So, the hp loss due to exhaust restriction should be minimal on the engine dyno.

Things get very interesting once the engine is installed in your Cobra. If you use stock headers and sidepipes (with mufflers), then you will undoubtedly see significant hp loss due to increased exhaust restriction. Probably on the order of 25 to 50-hp. This loss will be reflected on the chassis dyno. Bottom line is, you must consider exhaust system hp losses ON TOP OF powertrain losses. That is, when trying to compare engine dyno hp numbers with chassis dyno results.

Also note that the air cleaner, alternator, and other accessories will contribute to some hp loss, as well.

It's not just the powertrain that robs your engine of precious hp.

Tom