Rebuild or get a new motor?
 

I've got a 99 Silverado with a 4.3 that has rod knock..

My question is..... With over 350K miles and rod knock do I try to rebuild it or should I just find another motor?

If I can still rebuild it what internal performance parts are out there?

Well I would probably rebuild as it would be a heck of a lot cheaper than buying a brand new crate motor. Or if you find another motor with less miles in better condition it might save you some money on the rebuild.

I was looking around at online junkyards and found 3-4 4.3 with about 100K on them for $550.. I was thinking about going with that because I really don't know what I would need on that rebuild and figure I'd probably be spending more than $550 for all the parts.

Rebuild or replace (whether it be used or crate) is a difficult question to answer without first seeing the extent of the damage to the crank. If the crank is wasted, I wouldn't bother too much with your engine unless you can find a cheap crank somewhere.

You should be able to find lower mileage used motors for around that same price. If you find a higher mileage one that is running well, you could always go through it and freshen it up with new rings, bearings, and an overall cleaning of the heads, etc.

You can also find a v8 to swap in rather inexpensively. Get the under hood wiring, PCM, and engine all as a package.

Now I could be wrong on this one, but I'm sure Kyle or someone can shed some light on this. But I heard a rumor a few years ago that GM/most auto companies will buy your vehicle from you for research purposes if it reaches 300k original miles?