I've got Smith built 540's with good Chit in em AFR heads, custom cams, custom tuned ECM, CMI headers, 630 HP a side, I don't see how, numbers don't ad up, but good for u, I guess I'll take the 500's out of the Cig put em in the OL and do 90

Sadly, It won't.

That is pretty light, it is a lot heavier.

Powerboat mag tested the Vyper with 500EFIs and went 85.2 GPS and 86.5 on radar.

I had a 2002 Vyper with 496 HOs and went 79.5 GPS in freshwater. Would run 78 everyday.

Wanted to go faster but the hull was maxed out.

The boat seems pretty calm compared to the last two boat I have had at this speed. Do you think the hull is maxed out ?

I have heard that stock 500 efi's have put up dyno numbers close to 600hp. Completely stock, I spoke to a engine builder that threw one on the dyno before rebuild.

If you love the boat then by all means please enjoy modifying her. But bolt on parts are not going to be enough to satisfy your speed goals. They will just leave you wanting more! I would add a blower and continue to freshen the engines as needed.

Just remember XR drives will prematurely wear out if not break with the added power. Even with every upgrade available your still forced to use the stock junk gears...they WILL pit and come apart. Either have 1 or 2 spare drives laying around and plan on constantly rebuild them almost every season or buy a pair of IMCO SCX for about 30K.

500EFIs usually dyno around 510hp

Nope. You misunderstood. Or he did.

I've always heard they are closer to 470 hp.