Mufflers
 

I have twin 502efi's. trying to get that laast bit of speed I can out of my boat.

There are mufflers installed on the exhaust. How much HP is this causing me to loose? I know we can't be exact but?? I guess the simpler question is: Am I loosing HP? Am I loosing RPM's and therefore loosing speed?

Then: Is there a muffler that will not kill HP/RPM? Is straight exhaust the best way to run?

Depends on the mufflers. I have Gibson clamp ons, I can't measure any speed loss and I'm running a 700hp 524 through mine. But I can almost fit my fist through my mufflers too. Don't use the cheap inserts.

I have a nice set of Teagues. Open you won't loose any power, closed you'll lose a little up to 3500 RPMS at which point you should open them up. If your interested they're listed in the swap shop.