Early 2001 Block?

[Billman]

I just got back from looking at a block with a Julian date of C151. I would assume March 15, 2001. Crack-Free. Casting Number 12555506.

It has all the Tell-Tale signs of an Enhanced Block.
---Additional Blind Bosses on Sides
---Smaller Piston Spray Jets
---Additional Material on Main Caps between Center Bolts

Except: No Navistar Logo in Lifter Valley

Who Cast this Block, GM or AM General/Navistar?

Is it worth anything?

[rjschoolcraft]

It's only about a year newer than the one I used. Probably near the last of the GM blocks. The one I took out of my truck was actually about 3 months newer than the one I am now using. Splayed mains...

[AndyL]

How long did the transfer take? Haven't there been posts of people with the Navistar 506s in the 99 model year? I wouldn't have thought they would run side-by-side for 2-3 years.

[rjschoolcraft]

Around November 2001 is when the new blocks began production.