friend of mine is looking for this but would like to run 70-75 mph...

I doubt it will do it

how fast does a black thunder 43 run with twin 500 efi?

Mid to high 60's. I still remember one at the shootout a couple years ago. You could hear the noise but it was like watching a train pass.

My buddy has a 40 outlaw with 900sc that are making 1080 with six drives. Motor, drives and 1450 trans are all fresh. His runs right about 100mph. I think he wants 129k.

My 33OL with Tyler Crocker 509`s (522hp) was an everyday 72-74 mph boat ... I doubt a 40' would hit 65mph

we had a 36 outlaw with 500efis.. would only see 68mph on a good day..

I'd agree to that.
A bud with 575 SC's in his 40 OL would hit low to upper 70's depending on conditions and fuel load.
My guess would be mid 60's
That's a pretty heavy boat for 500 pony's per side

See ya,
Kelly