I'm no machine expert and this question really stems out of my own curosity. Firend next door has a Monte Carlo he bought about awhile back whithout (dumb, but he did it) it running, guy claimed it ran nut he took off the intake manifold to sell. We get the car running and there is a pretty bad bottom end knock. We removed the engine and started to tear it down, first thing we found was bronze colored metal pieces in the bottom of the oil pan and stuck to the oil pump pickup screen. We took the rod caps off and found that the bearing were toast. The pistons were also .90 oversized. How much farther can this block be machined or would it just be better for him to find another block?

BTW: Mortec says this is a early 70's 350.

 

I'd find another block. Most 350 blocks are safe at .060 over. Pushing it to .090 will probably have thin cylinder walls. Early 4" bore blocks are still everywhere. Find a good 010 casting and start fresh.

 

You sure you didn't mistake an 090 for an 060? Regardless, follow the above advice,

 

You can bore them to the water jackets....then pound in new sleeves

 

with a .90 overbore you'd have each hole overlapping the next one by about a half inch, except the end ones, they'd be out in the air at each end of the block.

 

.060 if it's been sonic checked.

 

Hehe, yea, your right, it's a 60 over bore. apparantly I have dexlexia.

Anyway, cant go over 60 anyway can you? The internals looked pretty new so what would cause the bearings to go out that fast? I was thinking lack of oil.

 

What ede is trying to get at is that even if it was bored "90 over", it would be .090", not .9"

If it needs further boring at .060, find another block. Even if the cylinder walls were thick enough to take more, pistons would start getting hard to find. If the cylinder walls are still in good shape, you could hone it, ring it, and not have to worry about it for years.

 

Wouldn't rebore beyond that. Take a close look at the cylinders for hone crosshatch markings, sort of a pattern of scratches. If still there and all uniform looking with no worn spots, the block might be a good one to rebuild. Need a crank kit and a couple new rods, really clean the entire block and new cam bearings. If it needs rebore at this point, might be way ahead to get a crate engine from GM, roughly the same money for a brand new engine.