The Stovebolt Site Forums The Parking Lot Big Bolts Another Heat Riser issue

If you have the means to give it a try why don't you fabricate a new heat riser to replace the missing one? If you re-drill the holes that were welded shut you should be able to put a new rod in and attach a flap to it. You can either attempt to make it stock and get a new bi-metallic strip as well so it functions automatically or run a cable and control it manually. When working properly it will fully open when cold and fully closed when hot so it would not be hard to manually operate....probably about the same as a manual choke, without being nearly as sensitive to position.

Tad