any tips on cleaning out the cowl?

That looks sweet. Did it make a noticeable difference in engine performance?

Yes, carb temps are lower, even in stop and go traffic. And at HI way speeds, the ram air also makes a difference, almost like a poor mans tunnel ram. Have not put a pressure gauge on it though. Since my daily driver and no choke, when temps fall bellow 40 degrees, I run an open air cleaner to get some engine heat.