X2 on the adaptors. Perhaps 55Chieftan can give you some ideas on fitment, too. If not, Pontiac Years Tech Forum is a good place for advice. http://performanceyears.com/ I was looking to do the same with my '63 Catalina. The 700R4 was large enough that major floorpan surgery was necessary. But, the 2004R wud fit with a few taps with a BMFH.
I just got my Wilcap adapter today. Assembling all of the components - got the Mopar starter, modifying the 2 barrel carb to accept TV and throttle linkage, looking into a new plastic display to move from RD1D2D3N to PRNDD3D2D1, thinking about a switch for the lock up into overdrive.... Should have everything ready for install before the spring arrives as I just put the car away. $575 for the adapter, $65 for the starter, $225 for the 200 4R core, $700 for it to be rebuilt with Torque converter... in for a penny..
I'm putting a Chevy 700 R-4 in my 55 with a Bendtsens adapter kit, but I sure need advice on building mounts. Keep me posted on your project.
You never said what kind of engine you are run. My friend put a T5 with a 6 cylinder in his 56 and it bolted right up. Just a thought.
I'd lean towards a 200R4 in a Pontiac only because the 700 is long and may not clear the frame X crossmember. They're fairly wide with the bottom offset to the right a bit, too. That said, if the stock hydramatic transmission is working, you don't need the overdrive. It's already a 4-speed trans and the gears in the back are likely around a 3.08 and it should cruise all day at 65.
I just installed the Wilcap Adapter in my '63 Grand Prix. The plate had to be modified and the spacer had to be milled, plus it took 2 weeks to get. Bendsten had the kit in stock.
I'm putting a 700 R-4 into my 55 Chieftain with a Bendtson adapter to a 57 347 and I thought building mounts would be my big problem. Now that I have an empty trans mission case for mock up, I find out it is one hell of a bad (read tight) fit in that tunnel. I'm looking at major surgery here and I'm beginning to feel I am in over my head. Has anyone else put one of these 700's in a tri-year Pontiac?
I realize this is a very old thread... 55yak - Did you get the 700 R-4 in you 55 Chieftain? If you got in, did you have to do a bunch of surgery on the tunnel?