I'm gearing up for this same conversion. from what I gather, you want to visit your pull-a-part yard and find a transmission out of a 2000-2002 V6 mustang or F150. They have the correct bellhousing and still early enough that they have the provision for a speedometer cable. Grab the yoke with the transmission (hell, grab the whole driveshaft cause they are cheap at the pull-a-part. The transmissions from the larger V6 F150 supposedly already have slightly upgraded guts than the smaller V6. But either one will be able to hold up to a mildly built pushrod motor. Transmissions at the pull-a-part yard run $150 and take about 30 minutes to remove.
If i'm not mistaken, they use the 164 tooth flexplate, block spacer plate, and starter. And the transmission is longer than our stock ones, so the stock driveshaft may be able to be used if you have it shortened. I just get the transmission installed, set the car on the ground, and measure. A local shop can shorten a driveshaft or make one from scratch for half what you'll pay online.
For cooler lines, I have one car with -AN fittings and soft lines running from the transmission to the radiator. I was just gonna do the same for my 4R70W swap.
I'm swapping the whole motor over to a holley terminator max computer that will run the engine and tranmsission.
