engine rebuild or replace??

[helimech2003]

So, I was out this last weekend and the engine started knocking. Pretty sure its a rod bearing as my last 4.3lx did the same thing. Anyway, there is a local machine shop that can rebuild it (short block) for me for $800 plus parts and I know its gonna need a crank at the very least.
I also found a 2002 4.3l out of a truck for $800.
The boat is a 94 so I know I will need a different intake manifold and I will have to change the core plugs over to brass if I go the truck engine route.
So my question is this....... Rebuild or replace with truck engine? And if I go the truck engine route will I need to swap the cam?
The boat is fresh water only.

 

[Scott06]

I’d rebuild what you have as the 94 probably has a mechanical fuel pump whereas the newer has no mechanical fuel pump provision. Also newer engine has a serpentine belt so none of your accessories will swap over

By the time you do this plus the intake I think you’d be at a higher cost vs just rebuilding what u have. Plus you’ll have a zero hour motor if you have the heads overhauled too. Last time I did just a short block the oiling issues that caused the bottom end issue also ruined a valve... that broke and dropped into a piston. Not much money saved by just doing the short block

 

[Scott Danforth]

Here is what I would do

stick with your motor, buy a new crank and go from there. buy a new set of 96 and later vortec heads and replace your intake with a vortec intake to take advantage of the vortec heads.

your could use the 2004 and swap over brass core plugs and marine head gaskets.....however your jumping 2 generations of motors with the 2004 so you would need to invest in a whole bunch of brackets and pulleys from mercruiser. because your stuff you have wont fit. you still have to purchase an intake manifold as well as a marine circulating pump.

cam is the same

here is come reading: https://forums.iboats.com/forum/eng...history-of-the-4-3-liter-with-casting-numbers

 

[helimech2003]

I'm glad I asked because I didn't even think about the accessories not swapping over.I do like the idea of the vortec heads though.
Again,thanks for the help guys.. Just gonna rebuild