Call Superior about their overhaul. We had our 1956 0320 narrow deck rebuilt by Penn Yan with Superior parts (investment cast cylinders, pump, cam, new mags, harness, plugs, etc.). It came back with a 2000 hr (TBO) warranty, parts and labor with only twice a year oil sample stipulation. The warranty is transferable to a new owner. We drove up to Penn Yan with the engine and had a tour of the facility and met many of the people there. They were incredably helpful and the engine was shipped back to Wilmington, DE freight prepaid. I mentioned at drop off that I wished the overhaul came with Bendix mags as my Stearman had been a test bed and built up with a 450 P & W for Bendix in the early 50's for them to test auto pilots in unusual attitudes. Nothing against Slic mags just an old soft spot it my heart for Bendix. It was returned with (2) beautiful Bendix mags. Maybe just a fluke. Give them a shout. The engine is going back on my old 18A as I write this. Just another thought, Jerry