Well, depending on the casting date, it's either from a 1970 pickup with 255hp, or a 1979 pickup with 165hp.. The TBC suffix denotes a 4-bolt main block, and the part number (3970010) is a very common block used in the 70's of which there were a few variations.. sounds like a keeper.. a set of vortec heads and a roller cam and she'll be a screamer..
95 Wrangler 2.5 Auto (stock for now)
81 Camaro 454/700R4 (high 11's, 3900lbs, 19mpg)
94 FS Blazer 6.5TurboDiesel (almost stock)
99 VW Jetta TDI 5-speed. 50+mpg, will go 145mph.. Not stock...