RE: Great planes ultimate 160
Tater1, I did a 1" hole on mine and I have no fuel coming in through it.
Great looking setup so far!
BTW something else you might want to do is solder a small 1/8" brass tube into the plate that is on the bottom of the carb with a barb and run a piece of fuel line from it to the inside of yer fusalage. I had to with my dl50. Something with airpressure levels changing, my engine ran no so good without it.
I had to drill the hole a bit bigger for the brass tube. I used silver solder.
The plate has an existing hole in it but putting the tube on it puts the outlet inside the fuse where there is less pressure changes (I think this is how it works) some people run the tube into a film bottle inside the fusalage.