I recently bought a 69 Firebird 2 dr coupe to restore, as Modified. Looking at the Transmission Tag today I found something to stump me...Here it goes the code is 74 PG 11604. I don't know if it is a 74 or T4. What is this a powerglide? Whats the ratio? 2 spd? And is it worth keeping in the car? Any help is appreciated......Chris