rrr1313

finally finished my boat project 454 stroked to 498 has nice power and sound great but i am only getting 57MPh at about 4300 rpm i feel i still have about 100-200 rpm left before wot this is with 1/2 tank of gas and 5 on board on a b1 22 this is on a 88 baja 226 i know its heavy and old but i wouldlike to get to 65 mph at least with this build, should i try to a 3 blade 23 mirage plus the drive is a 1.36 bravo x. an ysuggestions would be great, maybe if i ditch the 4 people lol.

Trash

Ditching 4 people will help. That's roughly 800 lbs less gear.

I think you would be better off with a 1.5:1 outdrive ratio. The 1.36 is limiting your prop selection.

Without knowing more specifics on boat weight, how the motor was built (cam, exhaust, heads etc) it is difficult to suggest an accurate path to 65 mph.

rrr1313

the engine is forged bottom eagle crank h beams and mahle forged flat tops compression is 9.6 with cheap vortec heads with the 100cc chambers cam is a stock 502 ho cam holley 750..the machine guy told me this is the biggest cam without switching to different lifters evertyhing else is stock ..i wanted to contavt bob for heads and cam package but ran out of money and wanted to get in the water before memorial. boat weight accordong to site is 3500lbs. I hope next season to get new heads and cam and valvetrain

Trash

Are you running stock exhaust?

Is the exhaust thru hull?

If its thru hull is your timing and fuel delivery up to snuff?

Switching props right now will not get you any closer to 65 mph right now. It's my estimation your engine should be turning at least 4800 rpm assuming everything else (fuel, air (in & out), and timing) is ok.

rrr1313

running 496 stock exhuast thru hull exhuast.Timing is another thing i need to check but since idle is good i havent wanted to mess with it.fuel I changed all lines expect ones going to tank

pqjack

never assume timing is right,,,should be the first thing to check...

dereknkathy

you are only turning 4300. a longer prop will lower rpm's. timing at idle means almost nothing. you need 30 to 32 at 3500. it is possible you have no advance and motor is trying to give power with only 8 or 10 degrees total. most likely you are at 10 or 15 atdc and advancing to around 15 btdc. get it timed. incorrect timing is about the biggest single way to lose power. and too much advance will roast your pistons, so don't guess.

rrr1313

i agree i had the timing light when installing motor but the dam thing ended up being broken. I will go get a new one and check it see another thing is I purchased the msd distributor from another forum member and I didnt check the advance springs on it.