What size is the stock stall in a 1994 pontiac formula firebird

 

12" is the "size".
More likely you meant what is the stall rpm??
The b-body was 1400rpms, have not seen much on the f-body stock stall but I want to say 16-1800rpms.
To put that in perspective, bolton cars benefit from stalls over 3000. Personally I would not buy anything less than a 2800 9.5" unit from Edge Yank or Vigilante. They really do drive just fine especially if staying down around the 2800rpm mark you can hand the keys to anyone and they wont notice a thing unless they get into the throttle.

 

On my 94 z I would call it a 1500 stall.

 

It's hard to get a real accurate number w/o a transbrake. But behind a stock motor I'd agree with about 1,500rpm. Of course, the more torque you apply to it, the higher the stall speed.

Rich