Cylinder Block Swap

[Block Man]

Hi, New to the forums, My question is, I have I believe is a 1979/80 Mercury inline 6 140hp. Serial# 5742675. I want to change the cylinder block out due to it being badly corrosive in the water jacket area with some pitting through leaking water into the exhaust. Can I use a block off a 115hp using my original internal parts? In other words are the blocks the same from 115hp - 140hp. Thanks

 

[Scott Danforth]

welcome aboard

no, you cant use most of your internals. you would at a minimum need new bearings, rings and pistons as they are a one-time use thing. you can reuse your rods and crank if they are useable. your machineshop can help.

why not get a complete running power head?

 

[Block Man]

Thanks for the reply. Don't really want to buy a new power head? So in other words I need a block from a 140hp correct?

 

[Scott Danforth]

if you swap the block, you need new pistons, rings and bearings and need to get the block bored and honed. a used and running power head is much cheaper