3spd or 4spd tailshaft? Help Please

I have an XP falcon with a 221 2V and I have recently fitted a single rail 4spd gearbox (apparently from an XD) and I need a tailshaft to suit. The XD-F all seem to have the larger universal joints that won't fit into my standard diff and obviously the auto tailshaft I have now won't fit into the gear box. Will a tailshaft from a 3spd early faclon (that suits the smaller uni joint (which I can get) fit straight up to the 4spd single rail output shaft? Or do i need to use a tailshaft from a later model falcon (which originally had a single rail gearbox) and get it cut and modified to suit the smaller uni joint?

Any help would be greatly appreciated as I know where both of these tailshafts are available (from my local wreckers) but these cars often don't last too long there.

i would personally get one made up using the xd tail shaft and have them put on xm/xp unis an it mite need to be shortned jst a little bit

Doesn't the BW35 output yoke fit the ringle sail? If so, then you need a tailshaft from an XP with factory 3-speed slushie... Naturally, this is where I tell you I threw one out a couple of years ago.

There is a uni joint from a 1970 Fairlane that is big one side (tailshaft) and small the other side (diff) - maybe that plus an XD tailshaft will solve the problem for you...