4 Speed w/ Overdrive Any Good?

I currently have a 383 4 speed, which I thoroughly enjoy. The problem is I like to drive this car alot and a 5th gear would make it more drivable.
So, would a 833 with overdrive be a good replacement?
Do they have the ability to hold up to a stock 383?
A rebuilt or hopped up 383?
Can I use the Hurst shifter I currently have on my 4 speed?
Is it a direct swap, bolt right in?
Any info would be helpful, there is one for sale near me and I am considering it as a way to get more mileage out of my car.
Casting number PP833 5330 with a 10 bolt cover number 99386 C99129.
The guy wants $650.

The trick with the OD's is the front bearing retainer. If your bellhousing has the small pilot hole, and almost all factory "A" bodies did including 383's, it will not bolt in. Shifter will work but the shift linkage is different, the OD lever is "reversed" on the front shifter arm. OD's work great on the street.