I've rebuilt mine 1.5x and replaced it 1x.

Rebuilds are more thorough than replacements but are also more expensive because they require more manhours to do.

In the way overpriced San Francisco Bay Area, a rebuild is roughly $3000 - 3500 (depending on what needs to be replaced).

My first one was $3500 and included a full top end rebuild, machine work, replacement of all basic extremeities like timing belt, rodding the radiator, replacement of a broken engine mount, etc.

My second one I couldn't afford a full rebuild so the simply did the heads on one side.

Whatever you do, have your radiator at least rodded and not just flushed. Rodding entails removing the top and bottom tanks and running a "rod" through the passages where the radiator fins are. This cleans out the excess mineral buildup which means less restriction to water flow and increased cooling efficiency.

So what's wrong with your engine? What are the symptoms?

Ray