drove my stock bodied '28 coupe [flattie w/ 4 speed] to work often.... had to wear slippers to drive there and then change over to the steel toed brogans...
I'd put a pillow on the floor, and sit on it. Then measure the distance from your head and the roof. Then that' how much you can chop it. Lol Seriously if you want comfort don't chop and channel all that much. Or if your using it for long trips. I have a 6 inch chop, and have to roll out of it. But it's been a lot of FUN for over 40 years now. Ron...