250 vrs 270

[thescooter]

hi i am back! in my search for extra parts to help rebuild my 28 1970 bertram baron i have found no volvo 250- drives. i have found many volvo 270s complete with transom sheild etc. what is the difference between the 250& 270. what if i buy 3 or 4 270s and change to270s also can the 270 and the 250 fit on each other transom plate etc. are the gear ratios different etc . also will a 351 fit for replacements for for the 302s . any ideas and suggestion will be great.
thanks the scooter

[olredalert]

Scooter,

-------Pretty sure the 250 and 270 will interchange.
-------More of a problem might be found with the change to 351s. Since the deck is taller on a 351 the engine will be wider. If you are talking about a 28 Baron with twins I believe the existing 302s are pretty close as they sit. The added width may cause the two exhaust manifolds to be too close together.
-------You will also be throwing off your exhaust centerlines to the transom to some degree. You may be able to fudge that though.
-------I lust for a 28 Baron so tell us a bit about yours if you have a chance............Bill S

[mattyboy]

I would have to agree with Bill on the size difference with the 351w, and the 250 and 270 are 95% interchangeable, there are some differences in the steering helmut and tiller arm spline and off course the prop shaft long hub short hub thingy but parts are easily found in bone yards and garbage piles as well as ebay I've seen a 250 lower bolt right up to a 270 upper not a problem, the gear ratios are the same for v8 apps look for a 250b or a 270 b that will be a 1.61:1 ratio ,
be careful on ebay many 4cyl lowers out there.
hope that helps and Pics we want pics ;)

[thescooter]

thaks for the info . pics will be soon . what is the difference between the 4cyl and the 8 cyl outdive i agree with you on the 351 width i think i will stay with the 302. is there any way to get more power out of the 302 without blowing the volvo outdrives ?i have a digital cmaera but my kids have put the pics on the computer when we come back from the shore. we have been in north wildwood for a month.

[penbroke]

The difference between a 4 cyl. drive and an 8 cyl. drive is the gear reduction ratio in the lower unit. The smaller engines require more reduction than an engine that has more power. This has been simplified to what are known as 4 cyl., 6 cyl. and 8 cyl. drives. I don't have all the ratios in front of me but the 8 cyl. has 1.61:1 reduction as Matty said. (Don't ask him how he knows...) :lookaroun

Frank
You can put a 200 drive on a 270 transom shield but you can't back up.

[olredalert]

------Your basic 270 Volvo drive is a hearty little bugger and can take a fair amount of horsepower if treated with respect. There are literally dozens of 302 stroker setups that you can research. The most popular being the 347 cubic inch version, I would think. To the Barons advantage is that your props probably arent going to see a bunch of air time. The shock of re-entry is pretty brutal. Do a couple of good basic torque-monster 347s and I think you will love it. You will have problems if you want the Baron to reach warp speed, though. Be realistic with your expectations, and you will have a ball..............Bill S

[mattyboy]

I think it goes

A 1.35
B 1.61
C 1.89
D 2.15



A and B are 8 cyl
C is 6 cyl
D is 4 cyl


I could be of a point or 2