803cc engine pullies & fan belt

[gtt1951]

I had to take the radiator out of my '55 4-dr, as I couldn't operate the drain tap (no antifreeze, so needed to drain and refill).
Whilst the rad was out (still is as, after vacuuming and brushing out with a paint brush and removing stubborn dead insects and small stones with a knife, the core now leaks) I took note of the fanbelt and paraphenalia.
The belt is the same width as those used on the series MM - big and fat! The pulley sizes are those to go with the fat belt.
I have a spare 803 engine and it's pullies are the same as the 948/1098.
Is this some form of "transitional" arrangement see pics?[frame][/frame][frame][/frame]
Note that the belt is a B-30 ("V" shape and 30" long).

[mike.perry]

According to "OMM" fan belt and pullies changed from B to A section at engine no 72610

[gtt1951]

According to "OMM" fan belt and pullies changed from B to A section at engine no 72610

Mike, my current engine number is A197421 - so what does that mean?

[mike.perry]

Don't know, just quoting from the book