340 Bore Question

[brentwab]

This has probably already been discussed and if so, I apologize. I have a 340 block that I am wanting to rebuild, already .030. One of the cylinders is too rough for .040, but .060 will clean them all nice and straight. Is .060 on a 72 340 block too much?

 

[70aarcuda]

I have owned two 340s that had been bored to .060 and never had a problem with them.....but the simple answer is to have the block sonic checked...

 

[moper]

I'd have it sonic tested to be sure. I've had (2) 340s 72 and 73 that took .060 with no trouble. But I've had one 73 that would have been left with a spot midway between the major and minor thrusts that tested thinner than .080". I had that hole sleeved as a result.

 

[damnimcooltom]

.040" is what Mopar suggests as max without sonic checking. I have a friend that went .060" with a 69 block once and he had overheating issues that he hadn't had before.

 

[brentwab]

Thanks for the quick responses! I will ask about having it sonic checked

 

[kielbasa]

when you say you want bores "nice and straight", only a sonic check and cnc (to find out much bores are off crank cl) will you know how far you can safely bore....

 

[Dustedu2]

Sonic as mentioned, I have a 69 stroker .060 over and runs 190-195° all day on 90° days in the city. Cheap aluminum radiator.

 

[RustyRatRod]

This has probably already been discussed and if so, I apologize. I have a 340 block that I am wanting to rebuild, already .030. One of the cylinders is too rough for .040, but .060 will clean them all nice and straight. Is .060 on a 72 340 block too much?

It will bore .060 and never look back.