All car water pump pulleys are larger than truck pulleys. The car shaft is also smaller. The truck pulley is deeper than a car.

ECG6316A is a common 55-56 damper, not familiar with EAG6316A.

The spacing of the 2 pulleys is about right for a 55-56 damper with p/s pulley bolted in place.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Today I was in the barn going thru a box that had e code 312 parts in it. There was the water pump pulley and it looked different to me so I compared it to one on a 1957 f100 272 engine. The e code pulley was almost an 1" larger in diameter.



This E code engine also had the 2 groove dampener but not like any I have ever seen before. The truck ones are back to back pulleys one piece, The other style Ive seen is the second pulley that is a bolts on to the dampener, This one is one piece with a 3/4" space between the pulleys.



So my question is are E code water pump pulleys different? Wouldnt this make the pump spin slower? would this increase HP? Seems this would cause a marginal engine to run warm?



# off the Water pump pulley is ECB-D and the # off the 2 groove balancer is EAG-6316 A



Thanks, Kevin

Kevin S in Akron, Ohio