No problem regarding the model numbers. The original Drake elongated 1.28gpf toilet is CST744E. At ADA height, its CST744EL.
There is an optional traditional-looking new tank for the original Drake (ST744E is the new tank number, ST743E is the original tank number) that makes the toilet a CST744EN or ELN, depending on whether it is ADA or not. (The "N" is for "new tank", the "L" is for ADA height.)
With the new tank on the C744EL bowl (the ADA bowl), the thing is 31-1/8" high, actually a little taller than the 30.5" that your CST744EL is. So that doesn't help.
That ADA bowl increases the height of the overall toilet by 2 inches. The CST744E (without the ADA bowl) is only 28.5" high. My concern is whether you're going to have enough room to service the thing if it needs it, i.e. replace a fill valve or a flapper. It would suck to have to pull the bowl off the floor and slide the whole thing out to get in there to change a flapper. And you may want to keep the ADA height.
So...some other options: The Drake II (CST454CEFG) is 30" high with a Univeral Height bowl (just a nudge under the ADA height). That might fit, but you would still have the issue of servicing it.
The Ultramax II one-piece is an outstanding toilet that is only 28-3/4" at the top of the tank. Universal height. CEFIONTECT. Double-cyclone flush. MS604114CEFG.
There is also a "lowboy" version of the Ultramax II called the Supreme II. Its lower tank might degrade the flush a smidge, but it will fit well and be easily serviceable at 25-9/16" high. MS634114CEFG and it's still Universal Height at the bowl.
One of Toto's best toilets, the Soiree one-piece, is 27-3/4", so you would have a little more room to get in there if you need it, but not as much as on the Supreme. MS964214CEFG. also Universal height.
When you go shopping, the MS (one-piece) ones come with a seat, while the CST (bowl and tank, 2 piece) ones don't. Remember that prices vary wildly at plumbing supply places, with 20-40% off list not unheard of when you are ready to buy. Terry's prices in the red box above are a good guide to a fair price.