The markings on my 1971 440 block read as follows:

G440
5 25 B(see below) C

I understand the G440 5 25 okay, but the B is backwards. It's my understanding that a regular forward B indicates .010" under crank journals, but what does the backwards B indicate? My main journals are standard, but my rod journals seem .010" under. Is this what the backwards B means?

Also what does the C indicate?

Thanks!

I think it meant what type of piston was used in the block at assembly. Possibly oversize??? or specialty??

My understanding is "B" = Main and Rods 0.010 undersized. "A" was 0.020 overbore.

As far as the "B" being backwards, it was most likely human error...

"C" is a mystery to me.

Any sign of an L with the C?

See the page at the link below.

http://www.hamtramck-historical.com/images/TSBs/1971/71-25-1_page7.jpg

No, no L with the C. That usually means low compression, but I read last night that C by itself refers to pistons (but what it means I don't know). I also read posts on other sites also asking about the backwards B (without answers), so apparently it's rather common. A mystery!

B is B, it's meaning does not change with orientation.

My guess is that the stamper missed the L.

I thought LC was only used on the 11:1 Max Wedgies. I've never come across a 440 with it.

From one of my books, FWIW:

Borrowed a good micrometer.

I definately have the B on the pad, but my main journals are about .003" in from standard, not .010" (and as said, I get .0025" clearance with Plastigauge on all mains). I suppose I could use .001" over main bearings (if I can find them).

My rod journals however are about .010" in from standard which may have been factory. I suppose however that this might be a replacement crank (although it is forged).

Does anyone have any used bearing shells I could borrow to do some experimenting with before I buy bearings? Thanks!

What is the VIN on the pad?

Is the second digit a C, D or F by chance?

Vin on the pad?

As I originally posted, the only things on the pad are....

G440 C
5 25 B

The B is backward.

The VIN pad is on the passenger side, slightly above the oil pan rail.

What does it say?

There are numbers on both sides of the block near the pan rail. They both say the same thing, which is: 2536430-9. There are no other markings anywhere on the block. The engine came out of a 1971 New Yorker if that makes a difference.

I was also courious why the upper thrust main bearing says P-72 and the cap one says P-43?

I read a couple years ago the c stood for 6-pack engine?

Hummm...I looked all along both pan rails at the very bottom of the block, and saw nothing. There is a letter here and there scattered around the block, but vertually nothing along the pan rails. Is that weird?

Okay, I found it after digging through a bunch of road grime. It reads: 1C253168 that's it. Nowhere near as long as the one shown above, but that's it. Above this, cast randomly into the block, is the letter D, and also N. I'm sure now that there are no other markings on this block.

So what might this tell us?