I'm currently running 575SC's and looking to pick up a few more mph's without going for new engines. My mechanic mentioned that there's a way to increase power by installing different pulley's and belts on the engines. He said this could potentially add 5 mph to my top end. I'm skeptical because this method sounds way too simple.
Has anyone heard of this technique to achieve more power?
Thanks.

I am not a guru for supercharged engines but by changing the pulleys you are increasing or decreasing the amount of overdrive to the blowers. The problem that I see that could arise from that is a conflict with the stock e.c.u.'s. I would imagine that they would have to be re-mapped in order to work right.

we have twin 540 blown, and changed pulls from 5 psi to 8 psi after we blow head gaskets a couple times had to get machine work done ring the block and head for high pressure gaskets and seen maybe 2-3 mph gain your call. not much for the workand $$$

Do you have labbed props? If not send them out to be labbed and you could gain 2-3 mph. Also look at air cleaner and check to see if K&N makes one for your set-up, again more hp equals mph.

575SC's

I hear that if you add intercoolers (superchillers or similar) that you can drop to a smaller blower pulley to up the boost to 7 and run the same ignition advance, same 91 octane, but need to go up on the fuel pressure a smidge. I do know a guy doing this who claims dyno numbers closer to 700hp, but I haven't seen any sheets. He has no special gaskets, nothing. Put 75 hours on them so far.

If you don't go the intercooler route, you will need higher octane fuel than pump gas. If you have a cheap source for avgas and don't boat enough to spring for a $1,000 intercooler then just cram an 8# pulley on it, get a tankfull of avgas and rock on.

If you are currently disassembled, head studs are worth the $$. Good ole FelPro Marine LocRing (not the kind that requires machining) should hold up to an 8# boost, but you gotta be sure you are not running lean or running too much spark lead. I'd rather have a head gasket let loose than hole a piston - you gotta have a weak spot somewhere, might as well be a cheap one.

John and Jay at Offshore-Performance.com in Grasonville, MD, did what MC described to a 2001 Top Gun with 575s. They added whipple intercoolers, and gained a few mph. (The owner is a member of this board and may chime in). John is also on this board; Pwrbt33.

Good Luck.