Just for the sake of argument.

I would be hard pressed to go past .75mm overbore on one of these blocks.

I had a 6.5 block sonic tested recently prior to a purchase. (That did not happen)
We found that generally what you are showing here is just about right on the money.

We did tests at 8 spots around the diameter and we did this in 1 inch steps starting at the bottom of the bore.

The scarry part was the little pockets that are present where the core must have been uneven.
We found one area on the upper 2 inches of a couple cylinders that had good thickness but then there would be a little pot hole if you will that was very thin.

The block in question was already .75 over and needed to go farther.
The basement was sound but I was very nervous about the bores.

If we had gone on out with it we would have possibly hit water in a couple spots and maybe had failures after it was running.

The seller insisted the block would go more but after doing the sonic I decided to pass on it.
I would have liked to cut the sucker open but the seller was adamant on selling it as a good block. (End of story)


I dont know if 6.2 blocks would be any heavier or have any more integrity in the cylinder wall thickness.

Regardless I would cap the plan to overbore any of these at .75mm

Far too much $$$ to find out down the road (No pun intended) that the sucker has issues.

Sonic testing is not cheap but I have a friend in the business that was also interested in the 6.2/6.5 block thickness so he did this one on the house.

I think we were just lucky to have found those pot holes because you could miss something like that real easy.

Every 45 degrees around the hole and do it on the inch starting at the bottom and work up.

Takes a bunch of time too.

Hope this offers some insight into this bag of worms.

Robyn