270 hp merc?

[chap2100]

I just purchased my 2nd 1989 chaparral 2100sx. The motor is a 5.7 with 270hp listed on cover. I checked and the block is date coded w/ a 1989 casting #. As far as I can tell everthing is original. (old). Did mercury make a 270hp magnum motor in or around 1989? All I can find is 260 hp info. My local dealer could not locate anything on it. Just wondering what if any differences are. If you are debating answering "10 hp" i will save ya the trouble right here!!!!

 

[Don S]

Re: 270 hp merc?

Since it all looks original, what is the Mercruiser SN of the tag over the starter?

 

[chiefalen]

Re: 270 hp merc?

You got a pic of that motor you can post?

I would love to see it.

 

[chap2100]

Re: 270 hp merc?

yeah I can take a photo. From what I recall from my last boat it looks identical.
I am pickling it this weekend so I will post the s/n as well.

thanks

 

[sundowner205]

Re: 270 hp merc?

For what it is worth, my '89 FW has a 260hp 5.7 OMC. Not a Merc, I know, but it is the same GM block, etc. However, on the spec sheet there was an option for a 270hp version. After doing some research I found that this option was a Holley carb upgrade. I'm not sure how many cfm's it flows, most likely 750, but anyway.

Perhaps it something as simple as a carb upgrade in your case as well. I could be totally off base here, however I just thought it may help a little.

Best of luck.

 

[chiefalen]

Re: 270 hp merc?

Had to be a carb difference from the stock one.

I didn't know you could order one from the factory, installed already.

Never seen 270 on the motor though.

Thats why i wanted to see a pic.

What did they charge for that upgrade back then?

 

[TilliamWe]

Re: 270 hp merc?

Not sure of the years, but back in the 80's when the 4bbl 350s were seemingly all called 260 by Mercruiser, there was the "350 Magnum", that had a higher rise intake manifold and a Holley carburetor on it. It was 270hp (at the flywheel)

 

[Maclin]

Re: 270 hp merc?

The Volvo 5.7's of that era (AQ271's or 570's) all were GM's and had Holleys and were rated 275hp at the crank.

 

[QC]

Re: 270 hp merc?

Looks like they started marketing a 350 Magnum in '86 as a 270 at the flywheel . . . lasted like that thru '89. Then in '90 they list it as a 270/240, and for '91 and '92 it was listed as a 240 (propshaft). In '93 they list the first 250 Carbed small block at the prop . . .

I got the image above from a .pdf that Bondo sent me. PM me if you want a copy. They are 4MB each and I have one from '62 - '92 and another from '93 - '04.

 

[chap2100]

Re: 270 hp merc?

here is the data DON S requested:
engine s/n: oc616674 per the tag over the starter
transom s/n oc567197
It does have a quadrajet carb. The intake manifold seems different. I believe this is the difference. I have pics that I will have my better 1/2 post as she is the computer guru!!

 

[QC]

Re: 270 hp merc?

Dave I sent the deal via email, but it got kicked back by gmail. I just sent it again . . . 4MB . . .

 

[TilliamWe]

Re: 270 hp merc?

And I could have been mistaken about the Holley carb. I do know for certain that the higher rise intake manifold existed and your engine just proves it. It was supposedly the "Z-28" hi rise manifold from the 1971ish Camaro that had a 350hp 350 option.

 

[Maclin]

Re: 270 hp merc?

The intake on my VP 350 275hp (1991 model AQ271C) looks like a performance version of "something". It does have the cast-in provisions for a spreadbore type carb. My brother and I hotrod MoPars so we are not as familiar with historical SBC stuff, but we both agree that this intake is a cast iron version of a high-rise performance unit. VP's used a 715cfm Holley 4bbl on theirs.

 

[Trent]

Re: 270 hp merc?

They also made a 270 hp from 1969 to 1972. They were usually mated to the old TR and TRS outdrives.

 

[chap2100]

Re: 270 hp merc?

Yeah, I found the info on those model yrs. That is why I 2x checked the yr stamp on my block. The info that I located also said they were trs drives.
I'd like to thank all for their input.

QC thanks for the pdf file.

ya know that intake manifold does look like the ol' z-28 manifold. Just don't tell my boat i am a pontiac/olds guy!

 

[TilliamWe]

Re: 270 hp merc?

ya know that intake manifold does look like the ol' z-28 manifold. Just don't tell my boat i am a pontiac/olds guy!

The Chevy engine won't mind that. It won the internal GM corporate engine war after all. He'll just pity you a little!