[79 Phoenix]

Originally Posted by 'ol Pinion head

Originally, the 500557 400 blocks used the 2.75" register cranks. That practice lasted at least a year/ well into mid '76 engine production. Later '76 model 400 blocks received the smaller register cranks, do remember checking a few.

For many years i had a Pontiac V8 engine core program going. On occasion I would pick up '76-78 500557 shortblocks, then simply shell them out for the good condition smaller register 400 cranks, as well as oilpans, timing covers, valley pans, & hardware. Two of the '77 500557's I stripped down, the stock cranks had the correct recess for a pilot bearing. Both of those cranks were needed in 4speed W72 TransAm engines where the owner had spun a rod bearing & was still wanting to run the stock small register 11" cast flywheel.

Block date is "A156" which I assume is January 15, 1976. Apparently my crank was cast later in the year, as the register is 2 1/2". Does this make sense?

Also I do plan on removing the pan to replace the rear seal. I should be able to find the crank date then.

I am considering installing a BOP 2-piece seal like link below...
https://www.ebay.com/itm/225319050821