I just finished my Eagle 580, This is my first fully cowled plane! Can someone look at the photos and tell me if they think this is enough ventilation? And I still have to neaten up the cuts LOL

Probably not. If you don't let the engine have enough air, you'll have all kinds of problems. The engine DEFINITLY won't last a full flying season. I would suggest cutting out the vent on the other side of the prop to start with. Next I think I'd go under & open up the bottom of the cowl from your ( I guess your fill tube) straight up to the exhaust cut out. The cooler the engine runs the better. ( within reason) Let us know how it goes. Something else I noticed. It might be a good idea to replace those metal bolts on your landing gear with nylon. It might save a serious rebuild on a hard landing. Nylon will shear off, not take part of the fuselage with it. Good Luck

The rule of thumb is to make the exhaust/outlet about 3x the inlet area. If that inlet in front of your engine head is about 1.5 sq inches, you need about 4.5 sq inches outlet. SOmetimes 3x is hard to get, and I settle for maybe 2x or a bit more. It's worked for me. Your plane looks nice!

The replies are right on. At least 1 : 4 inlet / outlet or more is the strongly suggested norms.

I think you might be concerned about the lack of stiffness or strength in the remaining cowl ... so what I do is cut out plastic or metal screen material (like door or window screen), fit it into place in the bottom of the cowl then lightly epoxy the edges of the screen to the cowl. Gives the cowl perfect strength, and it's "light and airy" for the engine cooling. I leave about an 1/8" space around the exhaust stacks and also finish the edges with light epoxy, too. Works great.

I would open up that exhaust area to at least twice it's present size