[Excaliber]

When I remove the side pipes and bolt on my shortys I can FEEL the difference big time. MUCH faster with the open headers.

Standard TKO type trans could either .6 or .8 in 5th gear, for sure it's overdrive, use 4th on a dyno. With the Richmond running in 4th (not 1 to 1 in 5th) I would expect a substantial drive train loss, that pretty much kills any dyno numbers and puts you back to square one.