Swapping to a 4.3 truck motor.

[MaxumJoe]

I’m swapping out my seized 2001 4.3 merc for a low mileage 4.3 vortec out of a 2008 Silverado.

My plan is to swap over the heads, intake manifold, dome, exhaust manifolds, water pump, starter, alternator, and base pan from merc and install on the newer fuel injected 4.3.

My question, is short block on the fuel injected 4.3 the same as the 4.3 carb merc, or is there something I should do be doing differently? Any tips?

 

[makomark]

check the cams to see if they match....and using brass freeze plugs is standard practice

 

[Dieter]

Keep the heads off the donor motor, swap head gaskets, freeze plugs unless stainless, cam is close enough between truck and marine to leave it alone. Keep the long block and ditch all other automotive components.

use all accessories off the marine engine check exhaust and intake for cracks, use merc electrical ignition and fuel components should be relatively plug and play.

Just be aware some 4.3s with 090M (metric block) casting will use metric threads for flywheel cover, side motor mounts, and starter bolts. Not sure why GM did mix and match threads but I'm sure it made sense to some desk jockey...when I did my repower I had to buy SAE bolts for the aforementioned locations. No big deal..