Driveshaft question and input on trans specs

[1991SSP]

All I like now is fans, coolant in the system and the trans topped off with fluid and my swap is complete.... but I have a few questions

I used dirty dingo mounts and a trans from a 2001 silverado in my 98 tahoe 2WD swap.. when It came time to bolt up the cross member I had to notch the slot for the trans mount bolt forward little over and inch.. put in the driveshaft and it's too short in my opinion, I am planning a 4/6 drop for it soon... is this normal for the driveshaft to be short?? the engine is slid as far to the rear as possible on the new dingo mounts,,, Are the later model 4L60E transmissions shorter that the original one that was in the tahoe before this swap?