Hemi block ID help

I can see that it is a '68 casting and was used in a '70 model year but I'm not sure what some of the other stampings mean. I think the '69 date is an assembly date but I'm not sure about the MN or is it an upside W? The WT is water test. Is the MN for Marysville Plant?

In the VIN the 0 is for '70 and the B is Hamtramck? So this block could be from a '70 Hemi Cuda or Challenger?

Here is a closer view of the VIN

MN42630035319

MN= Plant identifier for the Marysville engine plant
426= Displacement
3003= Build date October 17, 1969
5319= Sequence number

there's a fifth digit to the sequence number for 1970 model year & the partial VIN indicates it is/was a hemi'cuda

the B on the top pad and rail corresponds to 0.010 under size main and rod bearings
fwiw it's rather cool to see a block like this with original machining marks and stamps.

the crank would be undersize & the bearings oversize

now I'm confused...
oversized rod bearings means *smaller* rod journals on the crank?
I got the mains (if it can be bored straight and leave material it's good). I always figured it meant the crank rod journals were finished to a greater diameter for future cutting too

no, it is smaller diameter crank main & rod journals

it was done at the factory to use crankshafts that didn't machine with the desired surface finish at STANDARD OD size

on a block:
piston bores & lifter bores can be oversize on a factory block, because once the material is removed - larger is the cheapest way to go for a "fix"

block main/caps & rod/caps (because there are two halves) can be machined & returned to the STANDARD ID

So the 3 after the sequence number means 'Cuda? I did not know that. I've never seen any info on decoding the sequence numbers.

No, it does not.

It does match a 1970 Hemi Cuda though.

I do have an email contact for the car owner, I just sent him a link to this thread.

Way to go Barry! Bet you just made his day, just like your efforts have done many times in the past. I remember years ago, you hooked up the owner of an AAR with a kid who had his TA motor in his Dart that I sent you the VIN # of. Thanks for being an asset to the Mopar community.

The sequence number has nothing to do with what car it went into.

The VIN on the block told them it went into a cuda. Serial numbers were issued in groups or blocks so if you know the group range you can surmise what type of car it went into.

That could be good or bad. If the guy already has a "numbers matching" block in his car then seeing this thread isn't going to make his day.....

I should say that this is not my block. I saw the block sitting in a shop the other day and it was so clean and the stamps so clear that I thought I'd shoot some pictures of it just to see what it was. The engine appears to be complete with original intake, carbs, crank, rods, etc. all sitting there. I do not know the back story on the engine but if the owner of the car wants to contact me I could tell them where I saw the engine and they could take it from there. The shop was planning to rebuild the engine so if the car owner wants to buy it before it gets rebuilt then they'll have to make a quick decision.

I guess that would depend on whether or not he paid numbers matching money for the car but got a re-stamped block in the deal instead, otherwise I'd guess it wouldn't be a bad thing at all.

I'd be doing the happy dance big time if it were my car and there was an opportunity to get my numbers block back, has the block ever been hurt or repaired Andy?

Andy, I know what you mean. Could be quite expensive to obtain this block, and then build a whole new engine for your car, but may well be worth it for the owner.

Can we keep this thread going with updates? I would love to hear if anything comes of this.

Maybe they could work a deal to swap blocks?

Block appeared to be perfect to me. It is 0.030 over and it had old style pistons in it so perhaps it was rebuilt in the 80's or something. I didn't see any damage to anything. Crank looked factory fresh. I didn't spend a bunch of time examing parts since it isn't my motor and I don't know who owns the motor. I just happened to see this super clean Hemi block sitting on the floor and asked if I could shoot some pictures of it. I had never seen the rail stampings so nice and crisp. Thought it was the best original Hemi block I'd ever seen.

I know you are/were just trying to help and alot do it but this is why myself and many do not post specific info about others property without direct permission or in some cases our own cars on the web. Some do not favor the internet.

There are 3-4-5 on this board who could of helped with the vin info via pm.

I realize that but according to Galen's White Book "Any numbers found after those 13 digits are of no meaning."

I for one am interested in knowing how you identified this as coming from a specific car. I understand there is a link to the VIN but don't understand how the link is made.

- EM

I just checked the numbers and it's my brother's block so I assume you saw this at Gray's?

- EM

I had heard of the car before. That makes it easy.

This block matches the description of the block you were telling me about a while back.

Dan has this special computer that looks like something out of the Gene Wilder version of Willie Wonka and he just puts in any info that’s provided and it spits out the CORRECT answer. 😜 I’m not certain how he does it either but I’ve never caught him in an error.

Most of it comes right out of his head, have you seen that sucker?

If you have been hanging around smelling a lot of old gasoline and gathering up information on Cudas and Challengers you tend to know were a serial number would fit via your information you have collected. Sometimes the number is known via someone owning a car and asking about if you know of a motor or a body a motor came from. There are a few of these kinds of people doing this for years and it takes time to amass such information off sites and auctions, ebay on and on for years and years. I have been collecting since 1978 still do not have every 1971 Hemi E Body hardtop that was built. The 11-18-68 is the casting date and it went into a 1970 E Body and 11-11-68 usually is a 1971 Hemi Motor Build. First in first out was not used back in the day. I have seen a factory block stamped with .0015 on the Mains. When we rebuild the Hemi motor back many many years ago we had to use another crank that was 10 th. under because we could not find .0015 over size bearing and did not want to cut the hardness from the crank. Motor still running after 30+ years with that crank being changed and the original crank if the car ever get sold will go with it.