Unknown B

[CaptainCrutch]

I was searching through the internet when I found this beauty. It looks like a CA-31 cab on a B that doesn’t have the larger radiator. Just curious if anyone knows about it because it’s quite interesting.

[JoeH]

It says diesel on the hood, but I don't know anything about B's

[j hancock]

The early B-70 series did not have the larger aluminum radiator so the standard B shell was used.  The aluminum radiator came along to allow for higher HP engines to be properly cooled.  Production numbers of the standard B shell 70 series, I would speculate, is pretty small.

[Phase 1]

What makes it unusual with the small radiator is the L cab. I don't recall ever seeing that.

[h67st]

Tubeless tires too! That is unusual.

[CaptainCrutch]

Yes this is an incredibly unusual truck as before it was assumed that the smaller radiator somehow restricted the L cab from being used, but clearly that’s not the case. It’d also be interesting to learn how many of these were made with an L cab. It also begs the question to know if a CA-31 could be put on most other Bs, the only restriction being the size of the motor in relation to the hood of course. I personally prefer Bs with larger L cabs and if it could technically be available on most Bs then that would be a very interesting discovery.

[Maddog13407]

didn't the aluminum radiator shell come out around 56 57? or was it 58? when were tubeless tires first available??

[j hancock]

Point of clarification.  When I said B-70 series, I meant the 73, 75 and 77 trucks.  The B-70 model gasoline equipped truck utilized the same dimensions of the B-61.  The B-72 was gasoline powered and utilized the same hood with soft nose as the 73,75, 77.

I think the aluminum radiator came out in 1957 and tubeless wheels were introduced in 1955.

[CaptainCrutch]

Anyone know anything else about this truck? I can't even make out the model number on the hood. It looks like it's a diesel, due to that air cleaner, but I guess anything's possible. Honestly I feel like this is how the B models should have come, it'd certainly help with the space issues with the standard cab.

[mattb73lt]

I'd say it's a prototype, the engineering dep't. experimenting. There's some other pics(2) in the B Model books, showing a B-77 with the same serial number. In the second photo it sports a experimental cab with a one piece windshield. Someone told me that that was a fiberglass cab they were working on, but was never produced. Then there were the export B-81's that had integral sleeper cabs. I don't think any of those were offered on the domestic market.

[mattb73lt]

The one pictured here is a diesel. I'd say Cummins powered, B73/77, with that badging(that you can't read). 

[BOB DINGSDALE]

quite a few western mack's in the b-73 range with that rad were made in calif for western market. but with the b model cab.i think when they put the bigger power in that rad they just made the core thicker. my friends ltl had a 200 cummin's with narrow core  and i seen one with 300 cummin;s but thicker core.