Old 49er,
Welcome to Stovebolters! If you are trying to keep it more like original you have a couple of things you can do. If the old 16" wheels have been replaced with 15" you can pick up a little speed by putting the correct wheels and tires back on. This makes it set higher and I guess it does't look as "cool" by today's standards.
Another improvement would be a rearend swap. You can stay "original" if you can find a '54 rearend. Your '49 has a 4:11 and the '54 has a 3:90 but still has the enclosed driveshaft.
Another option is new gears (Patrick's etc.) which is expensive and should be done by a pro.
Remember, the old AD's weren't exactly built for high speeds. Make sure your brakes are in very good working order and your doors won't "bump" open. I put seatbelts in my '52.
Good luck!
Jim
