hseber, so you still use the vintage tranny, with an adapted tailhousing so you can use an open drivline, correct? If so,back in the late 50's before good floorshift kits like Hurst, hot rodders used the top shifting old tranny cases like your,adapted the 55 and up tailhousing from a Chevy 3 spd for use in open driveline cars.I belive the mainshaft from a 55 and up Muncie 3spd will more or less fit into the older transmissions.it might require some machine work.Its great to hear some guys like you are still daring to be different.