Don't mistake a natural and designed "turn" of the pitman (to make the balls line up to the spindles on the drag link) But I'm assuming you are aware of this and have considered this possibility.
The problem with heating the pitman arm and bending it back is you are changing the metal properties of the arm in so doing.
This similar to Ford's warning about a bent front axle (also forged.) Bend it cold.
Even so, you may be creating a crack.
Now having warned of cracking, bending may be possible. IF you have the means to detect cracks should they have occurred. Mag-Particle, Dye Penetrant, possibly even Ultrasonic (UT) All of these tests are done to welded articles to find cracking - including pitman arms that have been cut and shortened.
I myself would not. You have enough things that can go wrong in all the embrittled parts that may exist in an 80 year old car. Things you can't determine with near as much certainty perhaps. But the car was designed and built in an age and time which didn't mind design conservatism and it's negative effect on the bottom line.
Repop Pitman's are available. And flea market pitman's are cheaper by half - or more. Don't bother to waste the acetylene gas.
Joe K