I have the exact same set up and it's a piece of cake. I'm running the original 46 bell housing which bolts right up to the 261 (kept stock flywheel and pressure plate 11" Astro van disc). Front mount is the stock 216 piece. I'd use the adapter plate for the water pump that allows you to use the old 216 type water pump, this solves lots of issues over the 261 pump. Pre68Dave sells these on ebay.
I also have an adapter plate between bellhousing and T-5, may have to do a google search for those, mine was made by a local machinist. Best of luck
PS, make sure your 261 is set up for full pressure oiling, there's a pin near the big 1/2"npt oil outlet that MUST be pushed in to allow ALL oil to be routed to external filter.
