91 Mercruiser 4.3L to 01 GM 4.3L

[GulfCoast2572]

Hello!!

I have a 91 Mercruiser that has a rod peaking out of the oil pan. I was planning to rebuild the engine, but I found a 01 GM engine for sale really good price.

I do know I would need to change the freeze plugs, and head gasket seeing that we would be using it in salt water, and replace the intake manifold for a carb intake.

Is there anything else that I would need to change?

 

[matt167]

4.3L is muddy waters when you mix generations. You can make it work, but you will need a hand full of other 4.3l boat parts from a later 4.3l boat.. there are multiple variations of 4.3l and balance shaft vs non balance shaft is only the first hurdle

 

[Scott Danforth]

Is the 01 a marine motor or truck motor?

If a truck motor, you keep the heads and short block and throw the rest away

Core plugs, head gaskets, and circulation pump must be marine. The front accessories from the 91 will transfer over. The oil pan and exhaust will transfer over. You will need a new intake.

The distributor will transfer over

 

[nola mike]

An '01 may already have a composite HG and brass core plugs (mine did, although I wouldn't chance the HG). Possibly starter, water pump, a bunch of metric bolts, timing cover, intake (if keeping vortec heads), shift cable mount, possibly carb, iirc oil pan with some modifications, fuel pump (if yours is mechanical)

 

[jimmbo]

Is the 01 a marine motor or truck motor?

If a truck motor, you keep the heads and short block and throw the rest away

Core plugs, head gaskets, and circulation pump must be marine. The front accessories from the 91 will transfer over. The oil pan and exhaust will transfer over. You will need a new intake.

The distributor will transfer over

The Distributor might not comply with the USCG Regs

 

[jimmbo]

Hello!!

I have a 91 Mercruiser that has a rod peaking out of the oil pan. I was planning to rebuild the engine, but I found a 01 GM engine for sale really good price.

I do know I would need to change the freeze plugs, and head gasket seeing that we would be using it in salt water, and replace the intake manifold for a carb intake.

Is there anything else that I would need to change?

Edelbrock does offer Marine Versions of some of their Manifolds
I know some will argue with me, but the Cam of any Car/Truck Engine is not the proper Grind for a Marine Application. "Close" may be fine for Horseshoes, Grenades, and Nuclear Weapons, but not for Cams in a boat