If oil pressure is low, compression is down on one or more cylinders or you encounter knocking, blowy-by or crankshaft oil leaks, it's about time to rebuild the engine.
250,000kms
The cost to rebuild a Chevy 305 engine typically runs between $400 and $800 depending on the level of rebuild. This will greatly extend the life of the engine and improve performance.
If you pay a shop to do the rebuild, probably in the $2400 range. This does not include R&R the engine.
I just got an estimate of $2200 for a complete rebuild of my Camaro 5.7L / 305
18436572
Either a 305 TBI, 305 TPI or a 5.7 TPI
Depending how and where its driven,two wheel drive or four. but typically you should have no problem hitting 350,000k, it's recommended for a complete rebuild at 200,000k. Depends on how well you take care of it.
305 or 350
200
five quarts
The recommended spark plug gap on a 1996 Chevy C1500 with a V8-305 engine is .060"
The cylinders would need to be bored to 4", which would probably make the walls too thin.