97 Merc 5.7 / Alpha one outdrive

[Insanegtp]

I have a 97 Larson 226sei with a 5.7 Merc / Alpha one.... the motor seems tired, and for the past year hasnt performed like it used to... I just aquired I newly built 383 Stroker, built for circle track, built to make power 2800-7000 RPM I use the boat mainly for wakeboarding and ocean sprints to and from islands.. I am wondering first off, other than swapping all accessories between the engines, how much power and how high a rev can the alpha one handle?? The alpha is a little over a year old (I smashed a rock end of two seasons ago).... Let me know what you all think.... thanks in advance..

 

[redjmp]

Re: 97 Merc 5.7 / Alpha one outdrive

That motor may be usable BUT it needs at minimum a new cam and probably a new intake and quite possibly new heads with smaller valves...
That motor might not make enough torque at around 2500 to get you out of the hole.
Marine outdrives are not rated past 5000 rpm as far as I know...

I would not recommend that motor for marine use unless you have a very small/light boat with thru hull exhaust.

 

[GLENN M]

Re: 97 Merc 5.7 / Alpha one outdrive

being a stroked 350,it will make more torque throughout rpm range.you will have to change cam any cam makes power to 7000 will cause problems in a non racing type boat. head gaskets?frost plugs? your stock carb at the least rejetted. the 383 done right easily make over 450 hp.from what i have read on iboats thats to much for an alpha,that said iam sure you could be easy on it. can i come for first ride!

 

[Insanegtp]

Re: 97 Merc 5.7 / Alpha one outdrive

Glenn, if you werent in cali, I would deff say come for the first ride, I am changing the CAM and Intake to one that builds power from 0 - Up A little digging in other places told me as well 5000-5500 was max rpm for the alpha, but it can handle upto 500 HP...

 

[Bondo]

Re: 97 Merc 5.7 / Alpha one outdrive

but it can handle upto 500 HP...

Ayuh,... But not for very long,.... published limit is 300hp...

 

[GLENN M]

Re: 97 Merc 5.7 / Alpha one outdrive

i wish i was in cali,iam a little north in vancouver canada,we dont freeze we rust.