488 manifold and or engine swap.

iand464

Seaman
Joined
Jul 25, 2012
Messages
56
I just got a new elbow / riser for my 83 488 mercruiser because it was burning holes in the boot, and while changing it noticed a crack between the two exhaust ports going into the elbow. It is in the manifold. The crack is only in between the two exhaust sides not the coolant. I have never lost any coolant and haven't had any other problems. Is there any purpose in having the two sides or exhaust? How often does a crack lile this propogate? Ther are no exhaust or coolant leaks. A new aluminum manifold and elbow will cost a lot of money. Run it till something bad happens?

I am also considering a swap into a chevy motor. I got a lower mile 2000 goodwrench 454 out of a 3500 for free. I know I would need intake and exhaust manifods, electric fuel pump, modification to the stringers for the mounts and a 1.50 or 1.32 outdrive. The stringers are about even with the sides of the 488 oil pan. Looks like just bases for the mounts would need to be glassed in. How much else would I need to make a truck 454 go where a 488 was. Will the bellhousing bolt up? Can the 488's quadrajet be rebuilt to use on a 454? Can i use the distributor from the truck? More work than its worth? I like the hull and its in good shape Its a 16.5 ft freshwater only boat.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Re: 488 manifold and or engine swap.

A 4 cyl 470, right? You will be adding about 500 pounds to the stern of a 16.5 foot boat, and you will need a new outdrive with the proper gear ratio. I am not sure that that crack will be a problem as long as you are not loosing coolant. Have you changed the impeller in the outdrive? If not that may be part of the exhaust overheating problem.
 

iand464

Seaman
Joined
Jul 25, 2012
Messages
56
Re: 488 manifold and or engine swap.

The elbows inner pipe was rusted . A new elbow cured the boot melting issue. The 488 (4bbl 470) is working fine with the new elbow. The raw water pump impeller is new this year. As for the 454 I need to find a home for it.
 
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