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Old 04-15-2018, 06:03 PM
jggiedeman jggiedeman is offline
Join Date: Dec 2000
Location: Walla Walla WA
Posts: 63
Default Date code stamped in block near PMD

I have a 506 block, 1255506, E148. Figured it to be made May 14th, 1998. The code I'm referring to is actually not stamped but appears to be etched in in the block. Up front on left head bank next to the Inj Pump PMD. Reads YDD 05 27 J8. I figure the 05 27 refers to May 27th.

So what is the YDD and J8?

1994 K2500 ext cab. Recently repowered with; Non-cracked 599 block, factory compression, used old DSG girdle for main caps. Factory for what remains. Changed diffs to 3.42. Fuel economy Hwy 22.5 mpg US, in town without lcokup in 2nd/3rd - 18 mpg US.
1994 K3500 CC LB Silverado. Next project. Built for endurance, power and gearing. Plan on opened up intake and exhaust sytem, best cooling mods, 4.11 gearing 4L80E, followed by Gear Vendors OD. Need to be able to split all gears and have lockup in 2nd/3rd/4th. Tan interior cloth, Bad ass dark blue (coming) aluminum wheels and air ride (coming)
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Old 04-15-2018, 07:47 PM
DmaxMaverick's Avatar
DmaxMaverick DmaxMaverick is offline
Join Date: Apr 2001
Location: CA
Posts: 12,032

Assembly line info (date, shift, crew, etc.). The date may be correct (2 weeks after casting isn't unreasonable), but you'll need an original Dick Tracy decoder ring to make sense out of the rest. I've heard several explanations, but none of them the same, and they are not consistent from plant to plant. Your guess is probably as good as theirs, unless someone chimes in who actually worked at that plant, at that time.
1985 Blazer 6.2
2001 GMC 2500HD D/A
2014 Chevy Cruze Diesel - Fabulous car, no problems at all, but sold Nov. 2016 @ 55K miles.
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