E body NP833

Can I do this with out much modification?
I did it.
I order for the trans mount to line up, and, to not rattle on the T-bar crossmember, I had to grind off one mounting lug at the front shifter pad, and up the backside a bit; that was no big deal. Obviously the driveshaft will be too long. And you have to fabricate an adapter plate to move the shifter back to it's normal position. That's all.

But I took this opportunity to move the shifter about 7 inches back, to between the buckets. Then I raised it up high enough to install the top shifter mounting bolt from inside the cab. And then,I used an old Mr.Gasket Bang! shifter from the 70s, for it's short stick. Finally I fabbed up some new looooong shifter rods.
Then I fixed the floor.
Haven't missed a 2-3 shift since.

Having said all that, I think that has a close ratio gear set; 2.47-1.77-1.34-1.00.
Nothing wrong with that unless your engine has no bottom end, or this is gonna run hiway gears. Coupled with a 3.55 rear gear, the starter gear is just 8.77, and 65 is 2870 with 27" tall tires. That will require a lot of clutching in it's day to day use.
I like a starter gear of ~10/1, which would require 10/2.47=4.10 rear gears. With 4.10s. 65=3310
The earlier A-body boxs had ratios of 2.66-1.92-1.40-1.00; and the 10/1 starter comes to 3.73s, which makes 65=3030
But, the Early Barracudas had this; 3.09-1.92-1.40-1.00, and so the starter comes to 3.23s, and 65=2610

Can you employ less than a 10/1 starter gear? Well yes but it won't be nearly as much fun. I actually use 11/1 with a 430 hp 367. I have tried a lotta lotta other ratios, but 11/1 is a dump it and go deal, so my clutch lasts forever.

Alls I'm saying is, make sure you can use whatever ratio is in there, cuz you could be married to it for a long time.