>>> My vin#is 194675s120992, On the pad by the water pump I've got F0712HC , stamped smaller next to it is 120992, The number next to the bell housing is 3782870, intake manifold 3844457, exhaust 3846559. <<<
"F0712HC" doesn't look right to me, either. The number should end in "HO" ("HC" was used in full-size Chevy's), so possibly you misread it or perhaps it is mis-stamped slightly.... but, what further puzzles me is that serial 120992 was built in late June, yet your engine was assembled July 12, which does not seem credible. I think the engine and frame were stamped very early in the assembly process. So, unless a very serious problem was found with the original engine before it left the factory, and a new engine was installed and stamped in a repair bay several weeks later, this engine/vehicle date combo isn't correct. There's no way to verify that, it's only a possible explanation that stretches credibility because it requires you to believe that 2 rare problems occurred (a bad engine and a mis-stamp), which is unlikely.
Exhaust manifold is correct, as is intake and block.
Have you checked the number stamped atop the left frame rail, in the vicinity of the rear upper shock mount, to see if it also contains the "120992" code?
