This is a set of plans for a T bucket frame that I have been using for the last 15 years or so. To date there are 9 cars with this frame under them on the road. I would hope to add your T to this list.
The chassis is set up for a small block Chevy, but most all of the 4 cylinder and V6 engines will fit also. One of the finished cars is running a flathead with this chassis. If you are planning on using another make of engine, you will need to add to the length of the front rails. Measure the engine you want to use from the water pump flange or the lower crankshaft pulley, which ever one is the furthest forward, to the back of the most rearward head. If your engine has a rear mounted distributor, to the back of it. Now subtract 33” from this measurement. This is how many inches you will have to add to the front frame rails.
I use 1-1/2” x 3” 11 ga. Tubing for my chassis. Some like 2” x 3” 10 or 11 ga. tubing. The choice is up to you. All of the dimensions here are for the 1-1/2” x 3” tubing, so if you use the 2” x 3” tubing you will have to make the dimension adjustments. For the frame you will need to buy a 20’ length of 1-1/2” x 3” 11 ga. tubing and 2’ of 2” x 3/16” wall round tubing.
The drawing below has the dimension for cutting your tubing. To keep a clean look, layout your cuts so the seam in the tubing is on the side of the frame rails. Before you start cutting, lay out all the pieces on your tubing. Lay out the front main rails on each end with the 60 degree angle toward the center of the tube, then lay out the kick, rear rails, and then the rear crossmember.
The piece of tubing for the rear crossmember needs to be trimmed back on each end to form the caps for the side rails. Below is the layout for it. You will be cutting 3 sides off leaving 1 side as the cap.