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Upgrading 305 to 350

J

Joel Kilichowski

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" I am looking for info on pul

" I am looking for info on pulling my 1986 305 (chev.-OMC) because it's way underpowered for the boat, and powering up to a 350. The problem I am running into is knowledge of parts I can use from the 305 to the 350. Carb jetting setting, manifolds, fuel pump etc...The dealers all want to sell me EVERYTHING new of course, but Im pretty sure everthing will switch over; just need to find new jets for the carb. Does anyone have some facts on this? "
 
" Joel, the swap is straight f

" Joel, the swap is straight forward. All the parts interchange between small block Chevys up to 87, which have different heads (centerbolt) and intake (which has the two center bolts at a different angle), but can be drilled to match. You would have to modify the carb though, depending on what carb yo have now. If your motor now is still in good shape, I would install a set of Chevy "Vortec" heads, intake, and carb. This will add about 35hp. "
 
" Daren is mostly correct, but

" Daren is mostly correct, but the correct year is 1986 then 1987 they went to the center bolt. The other thing is that the 87 and up has a different bolt pattern on the back of the crankshaft so you would need a different crank-to-outdrive coupling, very expensive about $500.

Bob "
 
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