I fiddled big time to get a Weiand single plane to work on the 383, it was good and it was scary but the bottom end still wasn't what I thought it should be. I switched to a Performer RPM and she's a night and day difference with tons of bottom end grunt and still goes hard to 6000 RPM. The Weiands up for sale. No more single planes for me (that last 440 should have taught me).