boring out the 3100

[93grandprixse]

is it safe to bore out a 3100 .120" just curiouse because this would bring me to .020" over a 3400 bore and i could use the weisico forged pistons...

also, has anyone heard about copper ringing instead of head gaskets?

[bszopi]

Its been done before, but I'm not sure its 100% safe. If you did it, I would definately get the block sonic checked before I did anything else. You'd probably be better off finding a 3400 block and boring it .020" over. I know I wouldn't install forged pistons into a block that has been bored .120" over. No reason for the forged pistons as the block will probably fail before anything else

[93grandprixse]

iv heard from a guy that used to work at gm that you could safely bore my block to 3500 because its basicly the same thing... i assume he was false?

[bszopi]

The 3400 blocks have more meat to them than the 3100 blocks. And the 3500 is a slightly different beast. Not sure on wall thicknesses between the 3400 and 3500, but there are some other machining differences between the 2.

[Azrael]

I've heard of someone boring there's out to 3.3L.

[montess408]

the difference between the 3100 and the 3400 is .120 and the difference between the 3400 and 3500 is .080
so i think if sonic checked before boring the 3400 can be bored out to the 3500 bore but to bore a 3100 .125 is riskie !
i heard air motor's boring out 3.1 .100 to make a 3.3 so maybe that could be done

[Superdave]

Don't risk it.. 3400's are easy enough to find.