Hi @Rod Stewart
Yes, you will be within 1mm of error exiting the Challengers shell. Sorry, I don't have a pattern to share but here is how I measured it on my smoke units circuit board.
1. Start with your old "S" funnel screwed in place. Then mark a line across the circuit board at center of your existing smoke funnel. Your new funnel needs to exit the shell centered in the same location (white arrow). Note: my line is too far forward.
2. Make a mark at the back wall of your smoke fluid chamber because you cannot drill a hole past this mark (yellow arrow).
3. Remove the "S" funnel and mark a line down the center of the circuit board (blue arrow). This will give you a crosshair for your new funnels center mark on the circuit board.
4. Because that LionMaster Big Boy #4011 had a dual purpose smoke unit for both whistle and smoke exhaust you will find the funnel has an offset inlet tube on the bottom. You can either make a new brass inlet tube into that funnels bottom so its perfectly centered on your crosshairs lines. Or measure the funnels offset and drill into the circuit board next to the traces like I did. Notice after remeasuring several times readjusted I my marked circle back slightly before drilling into the circuit board.
I know we have two different LionMaster Challengers... so before you do anything permanent to your existing smoke unit make sure the height of your old "S" funnel is the same exact height as this new Big Boy dual outlet smoke funnel part #6101208201. If the height of the two funnels doesn't match correctly then I would not recommend using this new part.
Good luck Rod and post pictures!