Mercruiser V-8 305 swap with 350

[Luke59]

I have a 1979 898 V-8 305 with a cracked block. I have an opportunity to buy a Merc 350 out of a burned up 1998 or 1999 boat. I haven't seen the motor yet but the guy only wants $400.
My question is can anyone tell me if the 350 will swap out with my 305? Same footprint and mount to outdrive?
Thanks

 

[Bondo]

Re: Mercruiser V-8 305 swap with 350

Ayuh,... At the very least you'd need a different Coupler,... Possibly a few more piecs...

 

[haulnazz15]

Re: Mercruiser V-8 305 swap with 350

I have a 1979 898 V-8 305 with a cracked block. I have an opportunity to buy a Merc 350 out of a burned up 1998 or 1999 boat. I haven't seen the motor yet but the guy only wants $400.
My question is can anyone tell me if the 350 will swap out with my 305? Same footprint and mount to outdrive?
Thanks

You might try to find out what outdrive was on that boat that burned up. If it was a Bravo outdrive, the transom plate, gimbal housing, couplers, and all sorts of stuff will be different. If it's an alpha unit, then I wouldn't think too much has changed except for possibly the coupler.

 

[Luke59]

Re: Mercruiser V-8 305 swap with 350

You bring up an excellent point. I just got through reading similar posts about 305 vs 350 swap. (I'm new to this forum so I need time to find my way around).
I realized my Outdrive I is an older 898 (pre-Alpha One?) and it appears the newer 350 will not just bolt on to it without some differences. By the time I add up all the "extras" required I might be back up to the amount it would cost just to get a rebuilt Short or Long Block 305.

 

[Luke59]

Re: Mercruiser V-8 305 swap with 350

I forgot to mention the 350 engine was bolted on to a Volvo Penta Outdrive. The boat was burned and scrapped. The Guy was after the trailer only; must have been a good deal.

 

[Bondo]

Re: Mercruiser V-8 305 swap with 350

I forgot to mention the 350 engine was bolted on to a Volvo Penta Outdrive.

Ayuh,... That changes Everything,... You said Merc 350...

You'll have the Coupler/ Flywheel issue to deal with,+ probably an Intake Manifold issue to deal with...
And,... A fuelpump issue...

You won't be able to use Any of the Volvo components....

That's all got to do with Vintage issues...
It's got Nothing to do with 305s, Vs. 350s....
No Way in 'ell I'd replace a Dead 305 with another 1.....
Why pass up 45 Free cubic inches,..??

 

[sarantis]

Re: Mercruiser V-8 305 swap with 350

Supposing that with the 350 you'll get its flywheel that is bigger than yours and the coupler as well and modifying a litle the flywheel cover you may have problem fiting the 350's risers to your exhaust Y pipe.unless you keep your 305's cooling system.In adition different starter housing(only the front housing around the gear).Not so easy job.

 

[Luke59]

Re: Mercruiser V-8 305 swap with 350

Now I'm confused Bond-O,

I expressley asked him if it was a Merc engine with a Volvo Penta Outdrive. For $400 I would jump at the chance for more Ponies and newer engine, but I want to make sure I know EVERYTHING that needs to be done.

 

[Bondo]

Re: Mercruiser V-8 305 swap with 350

Ayuh,... Volvo drives,... Usually have Volvo dressed motors....

Once you get'em stripped to the Long Block configuration,...
They're both Chevy's....

Mixin',+ matchin' Volvos,+ Mercs would be nothing short of a Nightmare.....

 

[Luke59]

Re: Mercruiser V-8 305 swap with 350

I understand. So, the fact that the Merc motor was married to a Volvo Outdrive makes the job much more difficult. So, those extra Ponies will come at a higher price. I understand the starter issue, I understand the coupler issue, but I don't get the fuel pump and manifold issues.

 

[Bondo]

Re: Mercruiser V-8 305 swap with 350

I understand. So, the fact that the Merc motor was married to a Volvo Outdrive makes the job much more difficult. So, those extra Ponies will come at a higher price. I understand the starter issue, I understand the coupler issue, but I don't get the fuel pump and manifold issues.

Ayuh,... I'm doubting it Is a Merc..... I'd sooner think there's been a Miscommunication...

The Intake issue is from the Head changes over the years,... 98 should be Vortec heads...
And,..
The later blocks don't have provisions for the mechanical fuelpumps,...
You've gotta switch to Electric,... Not that much of a Biggie....

 

[Luke59]

Re: Mercruiser V-8 305 swap with 350

I understand now and I am also questioning the communication. I will find out for sure when I speak to him again. Thanks! I've learned a ton here already.

 

[tmh]

Re: Mercruiser V-8 305 swap with 350

Just keep looking until you find one that swaps in easily. i replaced my 1985 305 with a 350 (early 90's I think) and it bolted right in, no problems. The one I bought was fully dressed so I even was able to sell a few parts from my 305 on eBay/craigslist. Just find out what year 350's will work for you, make sure you've got Merc for merc and go find it.

btw, bondo and others here gave me the knowledge on what would likely work for me, I know nothing. Ask questions when you're stuck.