Is .060" over "safe" for a 440?

Planned use is for a backup daily driver, and sloppy weather 4x4 driving.

Found a freshly machined, balanced, zero decked, 440 with .060" over pistons short-block for less than I can have my core 440 and rotating assembly machined, balanced, and assembled.

I vaguely recall max bore on the 440 discussions from a few decades ago, on the original Moparts forum. but don't really recall the overall consensus.

This would be finished off with a pair of 452 or 906 heads, whichever are in the better shape and clean up for the best cost.

Cam will most likely be a Hughes Whiplash, or a mild performance cam, nothing huge, just a good driver that sounds nice.

No plans to do any towing.

Without sonic checking it, you'll never know. Since it isn't a high powered race motor, I wouldn't be scared of .060" over.

Definitely sonic-check it, in my opinion.
I ran a .062-over Street Hemi for over 30 years with zero issues, but it had enough material to do that.
Based on cylinder wall measurements I've seen & done, that was fairly lucky.
I like them .200 thick finished, but there are plenty of guys running less with success.

i would have it sonic tested and check to make sure it is still useable.
I like to see a minimum of .160 on both thrust surfaces (cam side and motor mount sides) after boring

Same here, just run it.

My current 440 block is .060" and wasn't sonic tested until it was way past the point of no return during the last rebuild. The numbers range from "no problem" to "Huh....", so it's a classic example of....it is what it is.

I went . 100 over on a 426 block, raced it for years with a 4.5 stroke crank. It expired, due to breaking the crank. Sonic check, go from there.

"hey, buddy, can I take this block for a coupla days and have an engine builder sonic check it? If it checks out I'll come back and pay you for it"

Good luck with that !!

For a daily driver/beater mobile I dont think I would worry. But this was a .040" over 440 that we didn't check that was for my street truck. It found its way into the dragster, and well you can see what happened when it developed a crack and hydrauliced. It did run 8.19 in the dragster here in Vegas though, so may was a bit spicy for it anyway

IIRC, the sonic #s on my 440 + .060" block show at least one thrust surface in that .090"+ range.

The backup 440 + .055" isn't as thick as the best walls on the .060" block, but the thinner areas are better. Core shift is a b!tch.

I like .55 over ........... you can find pistons with out going custom

Gives a new definition to siamese bores

1/2 inch 50 thousandths seems like an odd figure, might
as well go with a nice even 5/8" and be done with it (literally )

.055 on a 440 is 4-3/8” a lot more ring combos avalible. I have pistons rings rods and crank, been waiting to do a block for awhile