Hole pattern

[Gary Dotson]

Cutting a proper hole is more difficult than a lot of people realize. George Willer even had difficulty getting it right. When he had my 57, he thought it was supposed to have vertical exhaust but the hood he had was for underslung. He dutifully went about making the hole, then later noticed the hanger under the rear axle. He just went to a lot of work for no good reason. 57’s with vertical exhaust are somewhat unusual and I really like it that way. It is certainly more expensive to use the underslung but I feel it might be the best way to go.

[radioguy41]

I'm in the process of converting a Lo-Boy to vertical exhaust right now. Back in 2018 I converted another to a vertical exhaust and used these measurements off of my FCub to locate the hole.

Click on image for a larger view.
It's about 6 5/8" up from the bottom to the bottom of the hole.

It's about 3 5/8" from the tank seam to the center of the hole.

As for getting smoke in your face, use a full 18" piece of pipe (I buy a 36" piece and cut it in half which gives me 2 exhaust pipes). A full length muffler on top of that with a raincap facing to the left and you should not have an exhaust in the face problem. I see a lot of pipes cut so the muffler sits just above the surface of the hood and I suspect those all lead to exhaust in the face, the muffler is too low.

Factory illustration, note how high the muffler sits:

Here's the way I see a lot of Cubs today. I can see why the driver might get exhaust in the face:

[Bob McCarty]

Here's a tracing of the hole in case anyone is interested:
The small end goes down the curve.

[Stoffregen Motorsports]

Using a hole saw at an angle has too many perils. The teeth of the cutter will make the cutter walk and it won't end up in the right place. Better to cut the hole head on and then get the final shape with a carbide burr on a die grinder (pneumatic or electric).

For transferring the shape onto odd surfaces, I use a light. Mark the general area of the hole, then using a piece of card stock with a round hole in it, hold that card stock above the panel and shine a light above it. Once you have the shadow in the right place, trace that out with a sharpie. You may need two people for this.

[outdoors4evr]

Sounds like John and Dusty just need to trade hoods.