You might look at SSDiesel for some heads. I bought some from him last summer. He swore they were made in the USA, Alabama I think. I can't say for the quality as I haven't taken them out of the boxes yet. Just had other priorities. They look good sitting in the box though.
1996 GMC K3500 Crew Cab Dually 8ft bed
Rebuilt engine 2/10 18:1 pistons, forged crank, Fluidamper, dsg gear drive timing, high flow oil pump, rebuilt GM8, turbomaster, Kennedy ECM, 4" exhaust, wrapped cross-over and down pipe, '98+ cooling, Duramax fan, aftermarket oil cooler and hoses
Rebuilt tranny 2/10