Anyone know what kind of speeds this boat is running with a HP500EFI?

My guess would be low 70's.

I had a 2000, 272 with 502 Mag and the very best I every saw was around 66 MPH. With a full load it was usually around 63 to 64 MPH.

The 275 has the exact same hull as the 272, same mold.

I would say easily low to mid 70's with an HP. My 272 with 502mag ran 67 with a Bravo1 and a mile or tow faster with the stock Mirage prop.

Yeah, I think low 70's. What is the cost to upgrade to the 500? My guess is that for the difference, you could get a 496HO, put a Whipple or ProCharger on it, and buy a NEW 496HO later for the same amount as the upgrade to a 500.

Your probably right. My dealer told me the 500EFI was about $20,000 upgrade over the 496?

i would estimate low 70's - I have a 272 Shooter with a 509 CI N/A carb motor pushing 529 hp (dyno) and on a good day with light chop I'll see 76+ or - at 5200. The HP 500 is 470 HP, and therefor, would be a little slower.

Ditto on the low 70's
that's what i have seen 25 o/l's
run with that engine,
it's roughly the same size boat.
jt