Mercury Outdrives?

[DonziNUTS]

I am looking to change from a Volvo to Mercury on my 18. My question is:
Is there anywhere I on the interent to find out what the HP rating for each Mercury outdrive? ex. Alpha, Gen1-2, Bravo etc? Any help or direction will be great.
Just a hint I have a 302 w/12-1 comp. sitting on the floor and a 68 Z-350 also.....I am talking major HP that is going in this 18.....any suggestions?


Thanks!
Mike

[Rootsy]

I am looking to change from a Volvo to Mercury on my 18. My question is:
Is there anywhere I on the interent to find out what the HP rating for each Mercury outdrive? ex. Alpha, Gen1-2, Bravo etc? Any help or direction will be great.
Just a hint I have a 302 w/12-1 comp. sitting on the floor and a 68 Z-350 also.....I am talking major HP that is going in this 18.....any suggestions?


Thanks!
Mike

alpha w/o HD gearset i'd stay under 300 crank hp... with HD gearset 350 crank is gonna be upper limits... bravo good for about 500ish... a few of us push the upper limits of the alpha and alpha SS drives... some live, some explode...

most power in an 18 hull right now... well, think somewhere around 4 digits...

Jamie

[Pismo]

That is a fairly light boat and the engines are fairly low cubes so you may be able to get away with an Alpha if you drive gingerly, lower pitch prop, let it rev, no big re-entries, etc. A Bravo would certainly be safer and you could easily upgrade to an XR if you have problems. Same transom hole so easy switch from Alpha to Bravo, just lots of dollars.

[Tidbart]

Start clicking for ratings. :yes:

http://www.mercruiser.com/drives3

[Woodsy]

I would probably go with a Bravo.... it should be darn near bulletproof with a a small block driving it... especially in a small boat.

That being said... you REALLY need to watch what cams you are using in your engines.... too much duration and you will get reversion. Thats a quick way to ruin (hydrolock) a great motor! More than likely you will need to swap cams out of those motors for a more mild marine grade, or look into dry exhaust.

Woodsy Von Outboard

[mrfixxall]

stick with your volvo,,,,,try to find a 290 drive it will handle 500 hp merc bravo copied the cone style clutching that the volvo has.installing a new drive you will have to change the x dimentions if its not correct it will cost you speed.i have a 270 drive and pushing a 425+ small block through it at 6200 rpn for 10 yrs and havn't had a bit of trouble.....

[MOP]

Try to find a tilt a trim setup for your drive it will hold some big HP more then most realize. You show me just one other drive ever made that has ever even come close to holding up like the Volvo, the only one that some will say did is the Merc TR's at nearly twice the weight and has a tranny to boot! I could go on as usual!

MOP

[boatnut]

Try to find a tilt a trim setup for your drive it will hold some big HP more then most realize. You show me just one other drive ever made that has ever even come close to holding up like the Volvo, the only one that some will say did is the Merc TR's at nearly twice the weight and has a tranny to boot! I could go on as usual!

MOP

I like the way you two think re. the Volvo vs Merc drives. Back in the mid-70's I used two Volvos on a Magnum for offshore racing and they were bullet-proof. However, the Merc TRS came along and the Volvos were no longer competitive. Some questions as we are considering repowering a '69 H&M 18' that now has a 250 or 270:
1) I always considered the Volvos to be limited to the high 50's due to lower unit design (regardless of HP or prop). Has new knowledge or props made this assumption incorrect? (I have seen speedmaster lower units on the Volvos and they would do the job but hard to find.)
2) How does the 290 lower unit compare to the 250/270/280?
3) What speeds are volvo users getting out of the 18 classics with the
latest prop designs?
4) We would like a top speed of 65+ so we can cruise 55-60, can this be done with a Volvo drive?
5) Which models have power trim (not just tilt)?
Thanks much for sharing your knowledge, Ed

[olredalert]

Mike,

-------No one thats posted has addressed the transom hole. Im sure you know that the Volvos hole is bigger than any Merc drives. This obviously creates a decent amount of work and refinishing on your 18 transom. Others have done it but I think thats another reason that Phil and others are suggesting keeping the Volvo. It would be a hard decision for me.
-------I know that TRS set-ups are heavy but I love em. I never cease to be amazed at my luck finding the only Corsican ever built with a 280/TRS set-up. I have lightened up the package a bit for this season with aluminum in a couple of places (heads, exaust Manifolds, etc). Cant wait to get it wet. Hopefully this week..............Bill S

[MOP]

Nice contrast Silver/Red!

[MOP]

Careful Red the Southern Boy is a thinking!

[olredalert]

-------Well, you never know what will come out of the woodwork, but I really thinK my C-boat is the only Merc. There were, of course, other 18s (one of them being Poodles X18) that came with the TRS/280 package..........Bill S

[Forrest]

I like the way you two think re. the Volvo vs Merc drives. Back in the mid-70's I used two Volvos on a Magnum for offshore racing and they were bullet-proof. However, the Merc TRS came along and the Volvos were no longer competitive. Some questions as we are considering repowering a '69 H&M 18' that now has a 250 or 270:
1) I always considered the Volvos to be limited to the high 50's due to lower unit design (regardless of HP or prop). Has new knowledge or props made this assumption incorrect? (I have seen speedmaster lower units on the Volvos and they would do the job but hard to find.)
2) How does the 290 lower unit compare to the 250/270/280?
3) What speeds are volvo users getting out of the 18 classics with the
latest prop designs?
4) We would like a top speed of 65+ so we can cruise 55-60, can this be done with a Volvo drive?
5) Which models have power trim (not just tilt)?
Thanks much for sharing your knowledge, Ed


1) Yep, you are pretty much right, but better props (Solas) and nose cone kits (Hydromotive) are mow available to raise that limit at a low cost.

2) The 290 lower unit is not much different than the 250, 270 or 280, but the 290 does have a good power trim system that you would want if you stick with the Volvo transom cut.

3) Better ask Big Grizz or DavidO that one.

4) You can probabaly 65 with Volvo properly set up with enough power. cruise will be 50-ish.

5) The 290s have the best trim system. The older 280T had trim but they are rare and probabaly not worth looking for.

. . . but, if you are done with the old Volvo drive, but still want to keep the Volvo duribility, then don't even consider an Alpha anything. After owning a Volvo you will hate the way an Alpha shifts, and hate it more when it breaks. Go with a Bravo I or Volvo SX for smooth shifting, relibility, and performance . . . but you'll have to go through the trouble of glassing the old Volvo hole and re-cutting.

[boatnut]

1) Yep, you are pretty much right, but better props (Solas) and nose cone kits (Hydromotive) are mow available to raise that limit at a low cost.

2) The 290 lower unit is not much different than the 250, 270 or 280, but the 290 does have a good power trim system that you would want if you stick with the Volvo transom cut.

3) Better ask Big Grizz or DavidO that one.

4) You can probabaly 65 with Volvo properly set up with enough power. cruise will be 50-ish.

5) The 290s have the best trim system. The older 280T had trim but they are rare and probabaly not worth looking for.

. . . but, if you are done with the old Volvo drive, but still want to keep the Volvo duribility, then don't even consider an Alpha anything. After owning a Volvo you will hate the way an Alpha shifts, and hate it more when it breaks. Go with a Bravo I or Volvo SX for smooth shifting, relibility, and performance . . . but you'll have to go through the trouble of glassing the old Volvo hole and re-cutting.

Thanks for the info Forrest, do you know of good sources for 290's or is it just a case of searching the used market? I do like the idea of getting a complete package (e.g. Mercruiser Bravo 1) with engine and drive ready to go but that requires reworking the transom. We also have the prospect of dealing with the gas tank --- no signs of leakage but from everything I have read on this forum it seems like the deck should come off and the tank replaced ----- not a fun thought.

[Forrest]

I have two Donzi tank jobs waiting to be done. My '72 16 still has the original steel tank and it's got to go. My '77 X-18 tank is iffy. Both Donzis are out of commision until the tanks get replaced. Be safe.

I see 290 transom assemblies and drives from time to time on eBay for a reasonable price.

[MOP]

The Volvos are my favorites and very strong drives, an opinion I would hunt down an SX to get better shaped drive similar in profile to the Bravo. That in my opinion give you a little more top end over the old style Volvo's lower case configuration.

Phil

[DonziNUTS]

Thanks for the info guys!!! I just been sitting back on reading your post. I have some pondering to due so I can start looking. I am not scared to close up the hole for a Merc but I really have a tough decision here. I will let you know what I decide!!!


Thanks again!!
Mike