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Engine swap from six cyl to 4 cyl?

rantangdon

New member
Is it possible to swap from a GM 3.8 v-6 over to a GM inline 4 and mount it to the original stern drive system?

If not I have another option. I really don't want to get rid of my boat that I just love. I have an opportunity to purchase a complete Merc engine and stern drive. I know the mount hole is different as well as the control system but that all is available as a unite. Is there an adapter plate that can be installed or do I have to make my own?

Appreciate any help I can get.

rantangdon
 
Ayuh,... I believe yer V6 is a Buick, 'n the I4 is a Chevy, not an easy swap, 'n the gear ratio of the drive will be wrong,...

No adapter plates, just fill the transom with plywood, 'n glass, then cut a new keyhole,...
 
Bondo

So if I use the I4 in place of the V-6 the gear ratio will be higher or lower? I believe the I4 is high rev engine vs the v-6 at a moderate rpm. Does this mean that due to the gear ratio difference in the stern drive the engine will have to work 1/3 harder to maintain a moderate speed?
Rantangdon
 
Ayuh,.... Both motors run 'bout 4500/ 4800 rpms,....

The I4 will be a dog, with no power, with the V6 gear ratio,....

The V6 ratio is taller,...
 
Bondo

thanks for the input. I believe you just saved me a lot of money and many headaches. I understand it is best to go with the flow and install what the units were designed for.

thanks again
Rantangdon
 
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