348 Water Pump

[IMBVSUR?]

I got it from here

 

[427John]

My understanding is yes, the pulleys are different. The below pic is something that has been posted here a lot, so I assumed everyone had it.


View attachment 81829

While the small block dimensions look like they may coincide with the introduction of the reinforced center water pump pulley by pushing the hub back the big block numbers are a full 1/4 " difference forward which would require a completely different pulley with different offset,unless there was a thicker harmonic balancer that moved the crank pulley out a 1/4" introduced at that time too.