I found these two numbers on the front of an engine on a pad right in front of the passenger side head. Can anyone identify it for me?

V0428TDR

C8A168860

I have tried but cannot make them match up to the (limited) information that I have.
Thanks for any help.

V = Flint, Michigan plant. 0428 is the month and day of final engine assembly. TDR is the engine suffix code.
Nothing real special, although it "may" have a 4-bolt block.
350 SBC from either a 1972 or a 1980 Chevy pickup. (They used engine suffix code TDR in both of those years). If you can see the original paint color, orange would be the 72, blue would be an 80. Or, you can look for the casting number and date on the block to determine which of those 2 model years.

It had an Automatic trans, and was built in Flint, MI on April 28th of whichever year.

The 72 was a 175 HP version, the 1980 was 155 HP.
Here is a helpful link:

Nasty Z28 Small Block Engine Codes

Two listings for suffix code TDR

TDR 1972 350 175 4 conv. cab, a/t
TDR 1980 350 155 4 conv. cab, a/t, Cal

The year code of the VIN is an 8. In 1980, it restarted with an A so that block would be from 1972