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Posted By: 53&Me Mystery engine - Mon Mar 22 2021 06:50 PM
Hey all, I just picked up a 51' GMC 250 dumptruck that has an inline 6 with a chevrolet valvecover on it. I've tried looking up the number on the engine located by the dizy. F0222LB....if somene could please send a link to the engine #decifer information that would be super helpful.
Posted By: tclederman Re: Mystery engine - Mon Mar 22 2021 07:54 PM
My guess would be 1953 3100 216 engine. [1954advance-design.com]

Find and post the following:
- block casting code
- block date casting code
- head casting code
- head date casting code
- the complete Engine Serial Number
Posted By: drdoug Re: Mystery engine - Mon Mar 22 2021 10:10 PM
That looks like the later style engine number that started in '57 and ran through '62. If that's right, the F indicates Flint, MI manufacturing plant. 02 is the month - February. 22 is the day of the month. And LB is the service code.

LB was first used in '57, but for the 265 V8 - not correct. In '58, Chevy changed the service codes. L indicated 6000 series truck, and inline 261 engine. No LB code. In '59, L still indicates 6000 series truck with 261, but jumps to LC (no LB code), also a 261. Then in '60, the LB code shows up again, for 60-series trucks as the base engine, which would be the 261. Best guess is that the engine is a '60-'63 HD truck 261.

Here's the '60 VIK from the GM Heritage Center. Look to page #7 (8th page of the .pdf) for the service code shown in the attached image: 1960-Chevrolet-Truck.pdf [gmheritagecenter.com]

Confirming that ID, and narrowing the model year can be done with what Tim posted: casting numbers and dates.

Doug

Attached picture Capture2.JPG
Posted By: tclederman Re: Mystery engine - Mon Mar 22 2021 10:39 PM
If it is a 54-63 CHevrolet truck engine, here are locations of various "ID" codes. [1954advance-design.com]
Posted By: 53&Me Re: Mystery engine - Tue Mar 23 2021 12:44 AM
Thank you Tim and Doug, much appreciated. I'll start scrapping the crud off in a couple places. 😉👍
Posted By: 53&Me Re: Mystery engine - Tue Mar 23 2021 01:39 PM
ok, odly enough my head and block numbers are the same: head# 3836850 block#3769717
Posted By: 53&Me Re: Mystery engine - Tue Mar 23 2021 01:45 PM
I will be excavating the other numbers soon.
Posted By: drdoug Re: Mystery engine - Tue Mar 23 2021 03:25 PM
'53, The block casting number confirms it's a 261. That casting was first used in '58, and continued throughout the following production years, into early '63. That head is also the factory casting used on 261s.

From Tim's info, you'll see that the block date code is cast just behind, and slightly above the starter. You should see a letter-number sequence that will start with something like CON4 - ignore that, it's just the conveyor used in the manufacturing plant - followed by a letter-number sequence that decodes to the casting date. To see the date code on the head casting, the valve cover needs to come off. It will be driver's side, just a little aft of the carb.

In any event, great engine. If you are rebuilding, check thoroughly/magnaflux for cracks in both head and block castings. Trucks used hard were somewhat prone to developing thermal-stress cracks.

Doug
Posted By: 53&Me Re: Mystery engine - Thu Mar 25 2021 01:05 PM
I removed the valve cover and found casting number B152, I'll try to get the block number in the next day or two.
Posted By: 53&Me Re: Mystery engine - Thu Mar 25 2021 04:43 PM
So from what I can tell, the head is dated: February 15 1962
Posted By: drdoug Re: Mystery engine - Fri Mar 26 2021 12:31 AM
'53, that is correct on the head date. Let us know what you find for the block.

Doug
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