Is a GE T7 bulb similar to a GE T8?

The "T" number indicates the number of 1/8th of an inch in diameter. A T7 would be 7/8" diameter, and T8 would be 8/8 or one inch in diameter. But from what I can tell, the length of the bulb is the big factor most people run into. Most incandescent T8 bulbs I find are 2.5 inches tall over all, and T7 bulbs appear to be 2.25-ish.