1954 chevy water pump 3/8" or 5/8" groove???

I have a 1954 Chevy 210. 235 cid all original.....I need to order a new water pump but I'm not sure which one to go with or how to measure the one I have. Most websites give me an option of a 3/8" or a 5/8" groove pully.....does anyone know if there was a general standard size??? Seems that the 5/8" groove is the way to go, (or can someone tell me how to measure that....sorry, I'm a beginner. thanks!

 

my water pump is wrong on my 210 and its wider than it should be, Im switching it with a skinnier one..my "guess" is you will need the 3/8"...find a 3/8" belt and see if it fits into the crank pulley nicely

 

measure your belt width.

 

Are you calling me fat??

 

people in gl*** houses......

 

The pulley should be the same as the generator(if you still have the gen).

I put a 54 235 in my 51.The pulley should measure 5/8.

 

Thanks yall! It's was a 3/8" after all....and replacing the water pump finally fixed the over heating problem.