cant get over 50mph why why
 

Well I am new 2 this it s my 2nd boat I used to have a 27 ft sunray cabin crusier 350 stock . It hit 35 around heqvy boat at least 4200lbs . Nowi got a 21 ft baja hammer bought it with a cracked block on a 350 .so I sent it out had it done up heads done extreme marien cam5800 red line oversized 30.ooo elderblock 600cfm holly fuelpump thunderbolt ignition . No matter what I do I cant get over 50mph have tred changing props from ss to aluminum 17p to 23 p o and it was 1.47 gear ratio . A place out here told me 2 get gears to 1.32 so I did 1600$$$ later now I need a 17p to get to 48mph with a 21p I have a hard time geting out the water once out hits 50mph the place that did the motor work tells me I have min very min350hp I thought I would be runing a 21 p and doing at least 62+mph .and ft is a alpha 1 gen2 I had one pearson adjust carb and timing . Now someone else telling me maybe timeing chain or a exaust problem maybe air restriction.... can anybody help me I cant afford the marien shops no more at 95$ A HOUR just my gears coast me 960$ pluse 557$ for them to install

thats strange i had a 22 footer that did 59 consistently on gps with a 300 magnum smallblock and a 17 pitch prop. i think it could have used a 21 pitch too. It had a 1.5 ratio alpha with a snapped off skeg lol

i would think your not actually making 350 hp. Do a leak down on the motor and get the specs on the heads and bottom end.

What is the motor reving out to under load??

And the shop that said you had to regear your drive to get speed out of a 21' boat... don't ever go back there. ( I hope they are not the ones who built your motor)(

with the 1.5 and a 21p three blade Im guessing you should be doing 50 at least 1000 rpm below your 5800 rpm redline.

17p?? wholly hell man, how tight were you winding that thing????

Ya pretty much I around 4800rpm and no I had a diff place bulid motor there been doing it in the same shop for 45 years I am at about 5 gs in moter 1600 in ft and no father ahead . ( and just feel like theres no hope or money left could it be my manifolds air restriction. ...

first thing: did you check if your speedometer gauge is accurate compared to a gps?

had a 454 hammer that ran 65-67

1.5 with 21 pitch at 5000 should put you around 60 mph no doubt

if speedometer is accurate something is wrong with the engine

did you tested it on a dyno before install?

stock speedometers are sometimes close to accurate, but really shouldn't be depended on. download an app and see what gps says.

Ya I used gps on phone spedos bang on no I didnt put dyno test but u hear the cam u feel the power I mean with the 1.47 and 21p I geting like 45rpm can t get more in less I drop pitch and then all I get is more rpms and way better hole shot . I can be plaind in 4 sec almost and it flys up 2 50mph in no time I was going on glass water 50mph I go in 2 foot waves and against current and still do 50mph np cant figer it out I s cheak oil s fine no meatl no gas nada . Plugs r good never any problems with starting or anything running smoothly beautiful sound. I was looking for a place for dyno off the prop .I didnt want to pull motor again . I might not have anychoice but I kinda belive the motor place 45 years I dnt think hes screwing ppl thats all they do is machine motors tmr I put more specs offf the billl he gave me or some paper that came I belive with the cam

I will post it up tmr the compression I belive when the built it was 215 each around I have to cheak tmr I marked down somethings he told me and I did compression test like 3 weeks ago and it was all in the upper 185170 I will find ppw ty

if your running fine its probably okay im just anal and i do a leak down on everything, its the only way to know for sure.