340 block 1969

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mcgeesjlm73

mcgeesjlm73

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I just got 1969 340 block that I won't to build for my 1971 Demon.
Was cleaning it today and there is copper or brass ring around each cylinder.
Does this mean I can run the heads without a gasket never seen this before any help would be helpful. Try to post pics.

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Take those out. First they are copper and they should be stainless steel. Second, you should only use them with dead soft copper gaskets, not any other gasket although I've seen guys use them under Fel-Pro blue gaskets. I wouldn't do it.

If you are going to build a true 340 (not a stroker) you will probably deck enough off the block to remove the grooves. Either way, I'd deck the grooves out and if I had to, I'd remove a bit off the piston (ASSuming flat top piston) to correct compression ratio if you need to.
 
Why the stainless as opposed to copper, YR?

So OP, are you up from around Limestone Cove?
 
nm9stheham said:
Why the stainless as opposed to copper, YR?

So OP, are you up from around Limestone Cove?
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Because the copper will flatten out. I know way back in the day everyone used copper orings. When I started using them in 1984 we used stainless.

Also, to do it the correct way, you really need to oring the head and the block and put the wire in the head and use the block groove as a receiver groove. It will seal about anything you can throw at it and you are less likely to have oil and water leaks from the head gasket.
 
yellow rose said:
Because the copper will flatten out. I know way back in the day everyone used copper orings. When I started using them in 1984 we used stainless.

Also, to do it the correct way, you really need to oring the head and the block and put the wire in the head and use the block groove as a receiver groove. It will seal about anything you can throw at it and you are less likely to have oil and water leaks from the head gasket.
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Thanks for the info. I would think that if the copper was a very snug fit into the groove, it could not flatten and spread out very much... but I get the point.
 
Mos likely the block was professionally prepared elsewhere- look for other signs all the bolts bottom tapped? oil mods etc
If the copper is flattened out it will not hurt anything
If it ain't broke don't fix it check and see if all four corners are dead nuts on
I would check if using mls gaskets or gaskets with a fire ring larger than the o ring or which crosses the o ring
for high boost applications I used Bellevue washers as o rings
head could move around quite a bit and the spring in the washer compensated
 
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