Swapping a 488 merc to a chevy 305 merc

[Ridehard411]

I have a Christ craft scorpion 211 cuddy cabin with a merc 488 3.7 inline 4 .
I was wondering what was needed to drop a merc 305 v8 engine in. I already have the Outdrive and the back mounting thing for the outdrive, and of course i have the engine, but without mounting brackets or motor mounts. I could probably do this myself with my dad, and brother, but I do not have a place to do the work at. I live in Miami Florida, and I was wondering how much money should i spend on getting this baby dropped in correctly and reliably with brackets and mounts.

 

[Ridehard411]

Re: Swapping a 488 merc to a chevy 305 merc

I was wondering if anybody would be able to help me or give me advice so i can save some money or go about this the right way.

 

[Fishermark]

Re: Swapping a 488 merc to a chevy 305 merc

I already have the Outdrive and the back mounting thing for the outdrive, and of course i have the engine, but without mounting brackets or motor mounts.

Welcome aboard!

You would have quite a project ahead of you. The "mounting thing" for the outdrive is a transom assembly. When you say you already have it - do you mean the one on your boat already, or do you have a different one that came with the engine you are putting in.

If you are saying you have the one already on the boat, then you do have some issues:

-The outdrive is not going to have the correct gear ratio - that will need to be fixed.

- I don't believe the mounting tabs are the same width on the inner transom plate between the four cylinder and the v-8. I could be wrong about that - it would at least need to be checked.

- The four cylinder only has the single front mount in the middle - the v-8 will require side mounts. Are the stringers there and in the right place? Something to check.

That is just the start. If you love this hull, you might be better off finding a donor boat with the drive package that you like and swap everything over.

 

[Ridehard411]

Re: Swapping a 488 merc to a chevy 305 merc

I have the transon and the outdrive for the chevy 305, i also have the dual exhaust with dual stainless steel pipes.

Someone has given me an estimate of 1000-1400 depending on how long it takes him to align and get everything working in sync.

 

[Ridehard411]

Re: Swapping a 488 merc to a chevy 305 merc

Thanks for welcoming me aboard also, and one last thing, ON the specs for Christ Craft Scorpion 211, it said that max horsepower is 190hp - 230hp. I have the 190 hp on it already and the chevy 305 is rated at 230 , could it be possible that the boat came stock with either a 488 3.7 4inline, or a chevy 305 v8.

 

[Ridehard411]

Re: Swapping a 488 merc to a chevy 305 merc

Any Suggestions?

 

[Bondo]

Re: Swapping a 488 merc to a chevy 305 merc

could it be possible that the boat came stock with either a 488 3.7 4inline, or a chevy 305 v8.

Ayuh,.... That's entirely Possible....

Once you get the 470 out of the way,+ the 305's transom assembley set,..
You'll need to mock-up the 305 in place to see where,+ what height you need to glass in the New motor mounts...

 

[180shabah]

Re: Swapping a 488 merc to a chevy 305 merc

...could it be possible that the boat came stock with either a 488 3.7 4inline, or a chevy 305 v8.

Not only is it possible, it is probable. However, unlike in a car where the frame is identicle regardless of engine choice, in a boat the "frame" or stringers are completely different for inline and V engines. With that said, if you are comfortable working with wood and fiberglass then re-doing the stringers to support a V8 will cost more time and effort than money. Unless you are paying someone else to do the work.