I have heard that the early reproduction firewalls sold by the vendors do not have this hole pre-drilled, so perhaps this is a task folks must do themselves? I made my own cherry plywood so I haven't actually seen the pre-made reproductions. Anyway, here is how drilled the hole and it worked very well.

First, thanks to John Regan for clarification to me on how to locate the hole correctly. He helps a lot of people off the forum, including me.

I made up a block of wood to function as a drill guide. Then constructed a simple holding jig with a 69 degree angle (which will leave the necessary 21 degree angle through the block of wood)



Use a drill press and drill a 1/2 inch hole straight down through. The resulting block:



I was informed that there may be an easier way to make the block by first drilling a 90 degree hole down through the block, then cutting the 21 degree angle as a second step on a table saw.

The drill block is clamped to the dash with a sacrificial board clamped to the exit side. Masking tape was placed under the wood blocks to insure against any spintering as the drill passes through. On this particular dash the center of the elliptical hole is aligned 4" from the top of the dash and 6 3/4" from the dash center line. In this picture, the hole is being drilled from the passenger side and down through to the engine side. You need aroung a 10 inch long 1/2" drill bit to get this done.



The resulting carb rod hole.

Very good technicque for a difficult job. Keep the jig, someone will surely want to borrow it. Like me! I have a hand made (like yours) firewall for a late 1911 car. I have it completed except for the angled hole for the carburetor rod. I need to get with John first to find out the correct placement for the hole.

I can help you, now that I understand the interesting discrepancy on the drawing of the factory blueprint.

Ward