I'm working on my second Source engine now B 400/512. First was RB 440/496. Completed engine in 2013 and runs perfect. Engine builder said it was a good kit and needed very little work. Start assembly on second next week after I get a few parts. Both of these kits were purchased in about 2011 I think. I have not used any of their newer kits but I have no complaints of their older kits.