Engine Swap

[2SLO]

Hey guys. i have a 94 180 with the 3.0 mercrusier. I really want to swap a small block chevy, but im not sure of what i need to replace... I have ahold of a good running 350, but its not a marine engine. What parts should i look for to make it marine safe? Do they just have different bearings?  also, i need some info on how i would configure it to my drive unit. any help would be appreciated.

[Capt Ron]

Don't really recommend an auto V8 for marine applications. The V8's for marine applications are industrial engines and they may look like an automotive engines but here are just a few differences:
1) Four bolt mains... not easily found on automotive engines
2) Different pistons
3) Different heads due to cooling, operating rpms & etc
4) Cams are completely different
5) The distributor and wiring must be changed for marine versions for non-spark applications
6) Alternator must be replaced for marine application same reason
7) Starter must be changed including flywheel
Carb must be exchanged for marine application...no venting allowed.

I would tend to look for a used marine engine as opposed as using an automotive that requires extensive modifications that may end up being more expensive in the long run.
Cheers,
Ron

[2SLO]

all of the marine SBC's im finding are wayyyyyyy expensive. i appreciate the info!

any more info anyone?

[Black_Diamond]

I don't know if you will be successful AND safe in your automotive to marine SBC swap.  You'll spend a fortune buying all the pieces to make it work.  Seems you should be able to find a tired engine from a marine shop that does engine work, and then overhaul it.

[2kwik4u]

I've done the math in comparing piece mealing togethor a marinized SBC, as well as purchasing a turn-key crate motor.

If you factor in your time, the crate motor is the winner hands down. If you eliminate your time and assume you work for free, then it becomes a neck and neck race and it all hinges on how well you can plan and how well you can execute that plan without unforseen problems.

IMO, it's worth the cashola to get the crate motor unless you are doing it for a "fun" project. I you are going to enjoy the journey to get there, then by all means marinize an automotive engine, and have fun with it. If you are only wanting to see your speedo move another 10mph up the scale, then get the crate motor and enjoy the newfound power.

Just out of curiosity how much speed are you getting from your 3.0L? I see a pretty respectable 42mph from mine on a regular basis. Of course thats with a medium/light load and spinning the motor up to ~4700rpm. I'm hoping to get another 1-2mph from the smart tabs, but I'm not holding my breath. Considering my fuel consumption (20gal for a day of fun) I think I'll be OK with only going 42mph for some time to come!