Cracked 4.3L block, Options?

[strdrk1]

Location: Southern California
Casting: #14099090
Engine Serial #161687
1997 4.3LX gen+

Core plug popped out over winter, was hoping it didn't crack but confirmed after first test at the lake with a lot of water in oil.

Pulled engine and removed the exhaust manifold, intake manifold, and heads. Stopped taking things apart after seeing the crack along the cooling wall under the intake manifold and a crack above on the head surface going from water jacket to the head screw bolt.

Some of my questions:

1. What should i be looking for to replace the cracked block. Will a bare block work with swapping all internal parts work? Will getting used automotive short block work with swapping all marine accessories. rebuild a short block with new internals?

2. Is their anything i should worry with the heads and parts or internals after probably going 10 mins at 3/4 throttle with the oil having water in it. I haven't taken anything apart after removing both heads.

3. The exhaust elbow where the tube goes into the elbow is a bit rusty, does that call for a new exhaust manifold?

4. what else while having the drive out and engine should i check or do maintenance.

 

[NHGuy]

You can get a new or used same gen 4.3 and just put in brass core plugs and a set of stainless head gaskets. It's worthwhile to make sure the exhaust is perfect. Any issues and you could lunch the engine.
If you want more power you can use good heads, d dish pistons, max cam, good quench, more cylinders...it never ends. But it's fun!
Maintenance; clean & paint the bilge, replace old brittle blower hoses, how's your pump, does the boat have an automatic bilge pump switch. fuel hose condition?

 

[Swimforshore]

I had the same thing happen to me after a early October freeze. Found a rebuilt long block for 1200 and didn't have to look hard swapped manifolds and never looked back. More than likely heads and pistons are ok. Cam and crank are a toss up probably require some machine work which just adds time and money to things let alone tools and material to make sure everything is done proper
Long story short if you're happy with performance or on a budget put back in what you took out. If you want more start looking v8

 

[Rick Stephens]

If you take out internals and fit to a new bare block you need to do it right - which means machine shop going through everything, probably new pistons, rings, cam bearings, main and rod bearings, heads checked for any cracks, new oil pump (would you reuse a part that costs $35 and can destroy a motor in 10 minutes?)

What you should really be asking is should you find a replacement block and rebuild it using whatever parts are good from your old motor. The answer to that is an unequivocal yes. But don't cut any corners. You cannot just swap parts over. You must involve a machine shop that can mic and measure and properly fit everything.

Then you'll have confidence that your boat is reliable, which equals safe, on the water.

Rick

 

[Swimforshore]

Well said Rick