Most of the swap brackets you find will be for 340/360 engines, which are narrower on the driver's side. You will need to cut and widen the bracket to fit a teener. Normally when people use a 318 bracket on a 340, you need to add a spacer between the bracket and the engine mount lug, but you're going the other way...
Trans Dapt has 340/360 brackets:
Engine Performance & Vehicle Customizing Products From Hedman | Hedman Performance Group
Your other option is to use a stock A body 318 bracket on the driver's side, and a truck bracket on the passenger side. Easy.
Oh, and about your driveshaft- the 727 is longer than your current 904, so you will still need to shorten it or get a new one made, and you'll need a 727 slip yoke too.
