Boring a 340

[nothingbutdarts]

A guy gave me a 1970 340 block. It's already .030" over and I wasn't sure how far out one can be bored and still be reliable for street/strip use?

Thank You!

 

[3404spdvaliant]

.040 over=4.080 is fine, no problems.

At .060 I would maybe sonic test the cyl walls, just to know if I might wanna compensate for potential problems.

 

[72Swinger340]

Just installed a rebuilt 340 that was bored out 0.40. Runs great.

 

[Petzschler]

i have a 1977 360 ( iknow, i know, not a 340) a believe me.. i can go to a .080" overbore no problem,
and with no reliability issues. another .030" shouldn't be a problem. always sonic test!

 

[damnimcooltom]

Always sonic test if you want to go greater than .040" over stock. if it's too thin, you may have overheating issues, to say the least.

 

[moper]

I test anything over .030 over, and everything going to a longer than staoc stroke. Some "great" blocks are usable for some things and not others...lol