The Firebird does not use a porch as does the "A"-body cars. Most of the companies out there ie: Ames, NPD etc. offer a "4-speed" conv. kit and also sell the pedals as well.
My advise to you is to print out the manual trans section from the assembly manual and be sure to round up ALL of the CORRECT parts before starting the conv.
Also, just to give you an idea, this is not an inexpensive undertaking. Just the parts alone, NOT including the transmission & shifter, shifter body etc. you are looking at $1500. Then the transmission itself can range from $1500 for a rebuilt Muncie to $3000 for a 5/6 speed of your choice.
So all in all, there are TONS of parts and a fair amount of cash to make this transmission. I would be very cautious using "used" parts. If you do, be sure they are the right parts and they are in very good condition. I've seen people make these conversions using incorrect, beaten & battered used parts and end up with a terrible conversion.
Bottom line IMO, do your homework and be sure to round up the right stuff. Good luck...