I hope you can help me with this !!

I have an 82 Z28 with the following codes.

Front stamp 151165303 K02 11 CMJ

rear drivers side stamp forward of bellhousing 3870010

Thanks !!

I show these numbers to decode as follows:

151165303
1 = Chevrolet division
5 = 1975
1165303 = Last digits of VIN the engine was originally installed in

K02 11 CMJ
K = Mckinnon engine plant
02 = 2nd Month - February
11 = 11th day
CMJ = 1975 350 CID, TH350/400, 145 HP, Used in Federal vehicles

Note: CMJ was also used in 1974 for police, but your numbers indicate it's a 1975 block. This can be confirmed by checking the casting date code on the bellhousing mounting area on the pass side.

Also the casting # you gave (3870010) should be 3970010 which is a common casting # for 350's. To check if it's a 4 bolt main or not you'd have to pull the oil pan and physically look. Also check the balancer on the front behind the crankshaft pulley. If it is a large balancer, chances are pretty good it's a 4 bolt main.

Scotter has everthing covered! I can add the following about the VIN.

151165303 The 1 after the year 5 is the assembly plant, Oshawa, Canada. No Camaros were built there.

Also by federal vehicles I think he means used in all 49 states and Canada but not in California. In 1975 this was a Chevelle\El Camino\Monte Carlo engine application. My info says 74 was last year for full size at Oshawa plant

Info from Chevrolet parts catalog No. 11.