Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

zbloom75 · Mar 27, 2012

Good afternoon.

I just purchased a 1997 Crownline 202BR with a Mercruiser 5.7L V-8, with an Alpha One drive. Does anyone know the horsepower rating for this engine. I'm having a difficult time locating it.

Thanks much!

Don S · Mar 27, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

Do you have a Mercruiser serial number? The service manual shows 6 different models of 5.7's ranging from 235 hp to 265 hp.

zbloom75 · Mar 27, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

OK162453. Thanks for the assistance!

Don S · Mar 27, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

You have a MCM 5.7L Alpha engine. Model # 457B100KT
It's 235 hp measured at the propshaft.

John_S · Mar 27, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

The online version of the SM doesn't show the 2brl version of the 5.7L. The paper manual I have does.

Does it have a 2brl or 4brl carb? The latter is 235HP. The 2brl is 210HP. I believe mercruiser only made the 2brl version in '97, at least that is what the '97 brochure indicates that came with mine.

zbloom75 · Mar 27, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

Thanks for the help Don and John. I do believe it is a 2brl carb.

I guess I was hoping for more horsepower.

zbloom75 · Mar 28, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

Thanks, Bubba!

Don S · Mar 28, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

zbloom75 said:
Thanks for the help Don and John. I do believe it is a 2brl carb.

I guess I was hoping for more horsepower.

I would be interested in finding out if it is a 2 or a 4, your model number 457B100KT has the first number as a 4 instead of a 2, so I assumed (perhaps wrongly) the 4 indicated the 4bbl carb.

John_S · Mar 28, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

Don S said:
I would be interested in finding out if it is a 2 or a 4, your model number 457B100KT has the first number as a 4 instead of a 2, so I assumed (perhaps wrongly) the 4 indicated the 4bbl carb.

Don, I don't think the "4" means 4brl. My serial number is: 0K017089 which brings up model: 457B100KS. Mine was made in Sept '96 according to Merc. it is slightly older than the posters engine. Mine was stock with a 2brl.

Don S · Mar 28, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

Well, that answers that, Merc always has been good at being vague and impossible to figure out it is by SN or model number. They seem to love to keep people in the dark about what you have.

TilliamWe · Mar 29, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

zbloom75 said:
Thanks for the help Don and John. I do believe it is a 2brl carb.

I guess I was hoping for more horsepower.

You need a "Gen+" engine from that era. Those have the Vortec heads. Yours does not. So while a 4bbl carb and manifold would help, you still aren't going to get the same power as a Vortec headed engine. Sorry.

John_S · Mar 29, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

Bubba1235 said:
Umm, don't think that is correct. his boat is a 97 and GM / Merc went to the Vortec heads in 96 for the 350.

Yes GM did, but Merc offered both until '98. You can sometimes see a '98 boat with a '97 engine as well. From the model number, the poster has standard heads, not vortec. All vortec (gen+) mercs were efi or mpi, until '98, when they offered the 2brl carb / 250HP version.

I agree with TilliamWe, if the poster wants the best bang for the buck, stock like HP, vortec heads and a 4brl carb and manifold. But, then again, thats what I did, so might be a bit partial.

John_S · Mar 30, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

No need for %. Merc HP numbers can guide you.

- Std Head 2brl alpha: 210HP

- Std Head 4brl alpha: 250HP

- Vortec Head 2brl alpha: 250HP

- Vortec Head EFI (like 4brl) alpha: 280HP

All ratings @ prop.

TilliamWe · Mar 30, 2012

Re: Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

Thanks John. I work afternoon/nights, so I couldn't explain to Bubba how they offered both motors those years.

I had a 1997 5.7LX EFI Gen + in my Chaparral 2135, and it ran VERY well! Felt like a nice strong 280hp!

Horsepower Rating - 1997 Mercruiser 5.7L V-8, Alpha One Drive

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