2005 RX8 Engine Rebuild

Purchased a none running 2005 RX8 with known engine compression problems. Rebuilt engine with a new engine rebuild kit. Original cat was melted down. Removed muffler completely. Removed cat, resonator assembly, cleaned as necessary for initial start up only operation. Engine is hesitant to start, will rev's very reluctantly to three thousand rpms. 5 minutes of running and cat / resonator assembly red hot. Unobstructed exhaust. Resembles an engine with 20'+ retarded ignition timing. Reluctor wheel installed correctly with white tab facing front of engine. Looking for suggestions Thanks