James... Good choice on the TA23!! Your right there is not much information on the TA23.. There is plenty of information on the RA23 which is pretty much the same car but with a 18R-C and a W50 gearbox..
The TA23 was put in place only for a year, thats why theres not many of them about. The theory is that Toyota produced a new body to replace the TA22 shape, but they still had plenty of 2T drivetrain's left, so they retrofitted them to the RA shape. When the pollution laws came in in 76 they replaced the 2T with the 18R-C with the pollution gear. Bad move, but hey? They replaced the TA23 with the RA23 mid to late 76.. This upgrade gave the RA23 14inch wheels (opposed to 13inch on the TA23), Park brake light and slightly different heater controls and other minor differences. If you can find a TA23, grab it.. There's not many left..