Best Exhaust set-up for a 350/300hp Magnum Motor ?

[2 Trick Rick]

I'm thinking about Lightning Exhaust with an ECU re-program and K&N Filter, The weight savings is a nice bonus also. Would anyone have any idea what this would up my Horsepower too? I was thinking 330-335pr. Engine, does that sound about right?

[bordsmnj]

30 hp would be wish ful thinking and even if you did gain that it would result in roughly 1.5 mph on the big end. spend the money else where. a really good "magic" prop would give you better gains (3 mph)for a fraction of the money.
just my opinion. -jas

[2 Trick Rick]

30 hp would be wish ful thinking and even if you did gain that it would result in roughly 1.5 mph on the big end. spend the money else where. a really good "magic" prop would give you better gains (3 mph)for a fraction of the money.
just my opinion. -jas
Yes, I'm sending my extra props to Throttle-Up also.. Than maybe later adding a set of cam's

[HTRDLNCN]

I think every boat is going to be a bit different.
You may or may not get the gains you want just
depending on how maximized your combination is currently.
on my 270hp/350 carbed magnum I replaced the stock mercs
and thru prop to GLMs and thru hulls and picked up an honest 3mph.
Many people told me I wouldnt notice any gains.
Maybe my engine was running too rich before and the
exhaust leaned it out just the right amount,I dont know.

[Marty Gras]

Merc EFI is "Mass Air Flow", so how do you think you will up your horsepower? Free breathing is one thing, engine load is another. If you improve the exhaust side, you MAY lean out the mixture. You need to make internal mods to the motor, then "work" the EFI unit for more power. Just remember, the Merc EFI unit has a REV LIMITER, so ALL OF YOUR WORK SHOULD BE DIRECTED TOWARD TORQUE, not horsepower. Torque moves the load, and horsepower makes it faster. Build a larger motor!!!