For a Lake Boat seeing those RPMs a BG Sea Demon 750 would work best for ya. Otherwise a Holley 750 is also suitable.
Vacuum or Mechanical? Personaly I like mechanical, but a properly tuned Vacuum secondary is also very potent on the water.
The only downside on vacuum secondaries,in everyone's eyes but mine, is adjusting the secondary opening rates. No problem. Today's market offers adjustable vacuum houseings where you can remove the spring without taking off the canister, it's been around for a long time now but they aren't as robust as the newer designs.
The other killer new option is the Billet externaly adjustable vacuum canister. It only uses a screw to adjust the amount of pull the diaphragm sees on the secondaries. Hallet19 will have this set-up added to his TPC 790-VSR carb as soon as it's finished at the shop. It's a way to really put the VS carb back in power.
BG Sea Demon's? Come on now...LOL
Now if you're going the 514 route....then definitely step up into an 850DP (Annular booster). The BG Sea Demon's will seem rich from the start but with some patience you can detune them a bit. I don't think they have Annular boostered Sea Demons, but if ya came upon a junked out one I could build it to specs.
The 825 Race Demon in my Avatar was a junker that inherited a new baseplate, all new polish/powdercoat, new gaskets, floats, hardware, boosters, etc etc. It can be done.
Second time editing this post...
Those RPMs are probably being limited by that little carb. It has straight leg boosters which are starving that motor. I would bet that a 750DP would fetch another 5-600RPM alone.
[ July 15, 2003, 09:27 AM: Message edited by: Hotcrusader76 ]