Engine decoding

[RodnRudy]

I'm sure you guys get asked this question a lot so I'm looking to you for help. I bought a 68 SWB Chevy fleetside that originally had a 6 cyl stick. It was swapped for a V8/350 auto. I've tried to decode the engine through internet sites and here's what I've come up with:
Engine code- T0105CMJ I get, Towanda, Jan, 5th, and here's the hard part
CMJ could be 1974 350 160HP 4bbl T400 Police, or 1975 350 145HP 4bbl THM350/400 Federal. And lastly 1980 305 Auto.
Now I don't think it's the 305 because the other number stamped on the block is: 16J199806. I believe this is the number that was stamped on the engine when it was put in the vehicle and the 1 represents Chevy and the 6 represents 1976 and the J is Janesville plant the other numbers the vehicles serial number.
Is everybody confused now? Oh and it has a two bbl carb on it but that could've been changed. Surely that engine didn't sit on the rack and not get used till 1980?

[bruceman1968]

RodnRudy, everything you posted so far, is correct. I have a book that also list CMJ as a Chevelle/Impala, 1976, 350cid, 145hp, th350 trans, 2bbl.
If you want you can check the date code on the block, but the partical VIN does decode to 1976.

[RodnRudy]

That makes the most sense to me. As far as the 1980 code, the light bulb finally came on, if the engine was installed in 76 it couldn't have been built in 80. Duh

[RodnRudy]

I got the engine pulled yesterday and checked the casting numbers on the rear of the block.
3970014 is the casting # Also on the left side bellhousing bolt boss is L 11 76. The right side bellhousing bolt boss has CONV2 cast on it.
Adding these numbers to the ones I previously posted, can any one help me figure out what this engine is?

[bruceman1968]

3970014 casting number is a 68-79, 350, V8.
L 11 76 date code is Dec 11, 1976
CMJ in 1976 is, a Chevelle/Impala, 350cid, 145hp, th350 trans, 2bbl.

[RodnRudy]

Thanks much for the help bruceman1968, now I can proceed with the rebuild!