Visual Difference between B&M 250 & 420

[CNC]

I have a B&M 250, I am looking for a B&M Megablower 420 . Is there a way of telling
the differnce? The one I'm looking at, the owner say is a 420....but looks just like my
250? Is the actual size (casting) bigger? Any other distinguishing features?

Thank you,
Randy

[Back4More]

a 420 mega blower

[US1 Fountain]

A 420 is obviously bigger. Notice the difference in pulley sizes. Won't see no 250 with a pulley the size of what are used on the 420's. Not sure if a 420 has the carb plate like the 250's do. I'm thinking not.

a 250..........

[greencard]

The 420's, except the very early years around 1985, do not have a top plate. All 250 blowers use a top plate. 420 top pulleys use traditional 6 bolts where 250's do not.