what motor 1954 Ford fire truck Big Job 850???????????

Looks like a big Y block. Any ideas???

Lincoln Y-block 317. LYB 317-341-368 were used 1952-57 Lincolns and 57 Mercurys. They were also in Ford heavy trucks 1952-57 and Ford medium trucks 1958-64. Truck versions were 279-317-302-332 CID.

Thanks G,
Any idea how to tell from the outside which one this might be??????????
[addsig]

In 1954 the 279 came in the F-700 and F-750, while the 317 came in the F-800 and F-900. The 302 and 332 LYB didnt come out until 1956.