Lowell,
You won't be sorry for using the Texas T dist. The WW&F railcar has one and it starts and runs well. (Note: You only use half of the spark advance quad with the dist) The WW&F car has a 1923 engine with the mag removed and light weight oil fins. The high compression head will help in a number of ways especially as the car gets weight added. The WW&F T weight is 3,500 lbs without passengers so the extra hp is a plus. Another thing we did was to add an under the hood oil dipstick. The sight glass kept leaking plus you had to get under the car to check the petcocks so the upgrade was a help.
I have a '29 Model AA Express truck and a '32 Model B pickup so I had to learn the "quirks" of running a T railcar. I enjoy it, especially when I have passengers who have never seen one. You'll have a lot of "WOWS when your car is on the rails.
Stewart