OK, I have determined the Olds 260 that was put in my 70S has the 5.57" water pump as it shorter and has the 413307 casting number on the pump. Now my 70S was non A/C so it should have had the 5" pump. It has a LT top water pump pulley with 3 grooves and the outside groove is larger. It has a 2 groove pulley of similar size. Does this sound like 70 or 260 pulleys? Anyone know the letters and the groove count? The alternator doesn't line up properly with any pulley, closest to the second pulley, a bit toward the rad. The power steering lines up with second perfectly. I spaced out the PS but had squealing at start up and occasionally break the alternator belt. I put the PS back where it was and spaced out the ALT to the outside pulley. I see it needs a bit more spacing, squeals even more. This is now on my 88 CSC with the mighty 260. I have a warm 350 in my 70S now with a Flowkooler 6" water pump and non A/C brackets with the alternator spaced out and aluminum pulleys. It's 4900 rpm shift points throw no belts or squeals.

 

Belt and pulley charts for 1970 SBO and BBO in the A-body cars. There are no versions of the fan pulley with different diameters in 1970.

 

Thanks Joe, I kind of thought so. This makes even less sense as the Non A/C alternator bracket should line up being a Non A/C Olds 260. I have only seen one style of Non A/C bracket on the A and G body cars.