700R4 Tranny Question

[wwotr]

I currently have a Turbo 350 in my 72 GMC Short/Fleet.
No Overdrive and it tachs about 2300RPM while doing about 60 MPH.
My Gas Mileage is not where I'd like it either.That's not that BIG of deal, but I believe currently I'm getting around 8-10 and would like to be at least around 12 MPG.
The current engine blows a little smoke on Start-up and seems to be getting tired and the $$ are not in for a new engine ....(yet).

So I figured I'd get a quote from a Local Tranny guy, who come highly recommended by my Mechanic and 2 other "Hot Rod" shops in my area.
I explained to him that I wanted a Tranny without any Shift Kit, that would except my Tired 350, and a NEW 350, that would be in the 300-375 HP range.

I asked him for a "Ballpark Figure" on a 700R4, Rebuilt,
and (if need be) the Drive line shortened Drive it in....Drive it out.

His "Worst Case Scenario" was $1500.00.

I thought that was an EXCELLENT price.
I was wondering what the Forum Members here thought.

Just an FYI...No I'm not a mechanic and Barley Posses,
"Shade Tree Mechanic skills", so doing it myself is out of the question.
Besides I don't have the room.