Bolt,

I'm in the process of replacing my Saito 180 with a G-38. As you did, I cut out most of the bottom to clear the spark plug, wire and cylinder head. Some was already missing from the Saito install so I could possibly fill back in a part behind the lower scoop. On the side I had to cut out about a 1 inch by 1 1/2 inch hole to clear the carb.

I don't think any cowl could enclose it all. The Fiberglass Specialties version looks like it might be a bit wider (?) so it may enclose the carb.

Overall I'm not worried about the open bottom and the carb is accessible too. (My G-38 is the B&B Specialties/Bennett version so yours could possibly have a different carb mount). I was actually amazed that the flywheel and magneto parts fit inside as well as they do.

Dave