Ok you have the loverly 3.36 or 2.97 low gear T56. They only made that in '93 and '94. Its really uncommon to find one these days. Here's why you're having trouble. Tremec closed their warehouse in TN about 2yrs ago. As a Tremec distributor, I have to get my parts factory-direct from Mexico. This means deliveries usually take 30-45 days from start to finish. Your 2nd problem is that this particular gearbox is well over 10yrs old. When these models are no longer being used in new car production; they take a backseat when it comes to production schedules. So Tremec may make that 2nd gear once a year for example.
I sold the last one I had about a week ago. PM me and I can put you on a back order list, but it might be 3 months or more before I have it.
group A, number 28 in the above diagram. You can't change the ratio's in this trans easily either. You have an oddball, 2nd and 3rd gear and an LT1 length input, you could probably use it as a core towards a new T56 from Tick, RPM Transmissions, The GearBox, Finishline Trans and a long list of others.
I'll make a couple calls and see if I can dig one up, but its not gonna be cheap, my retail on a brand new one would have been $210