duster pistol grip

I know this one has been asked a million times but I can't find a thread. I was wondering with my 73 duster which pistol grip would fit best it looks like the small, but then people are saying too short and then the medium one the 71 to 74 B body? I'll shoot a picture here of what I have. it works fine but its not a pistol grip like I've always wanted. thank you for any help or pictures. I do have buckets in now but would probably go with A bench seat when I put the car back to stock one day for now it's a drag strip car.View attachment 20140602_131723.jpg

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