I was wondering if I can convert my 49 fleetline to an open rear but keep the stock 3 speed manual trans. I know the rear i need just wonder if I can convert the 3 speed to accept an open driveshaft.
You'd need a different bellhousing for a 55-64 trans to fit; either a truck, or 55-on bellhousing. Don't know of anyone that made/makes an open driveline conversion for the 54 and prior trans. Butch/56sedandelivery.
are there any other mods I would have to make if I use a 55-64 trans? Does the bellhousing bolt right up without mods?
Your stock '49 engine and trans are supported by mounts at the very front of the engine and near the rear of the transmission. There are two small mounts at lower the corners of the bellhousing that control engine "torquing" (the tendencey to rotate under load) that do not support much weight. Any 216/235/261 bellhousing will fit your engine block. The light trucks have the correct bolt pattern for a '55 up p***enger and/or pickup trans and is what you need but you will need a trans that has the rear mount on the trans housing. The '55/'57 cars have no rear trans mount. You also need to keep the original small mounts at the bellhousing to control the 'torquing' movement. Alternatively, you could probably add some frame brackets and utilize stock '55/'57 p***enger car bellhousing and mounts, which are considerably stronger than you originals, and not worry about the rear trans mount. In that case you could use vitually any GM pattern manual trans. A Saginaw full sycro three speed would be a worthwhile trans to consider. Ray