Tom, just back from a week and a bit in Florida so it's time to catch up on some posting.
I've of course done the breather box mod. Got the carb rebuilt. I also added the headman headers first thing after I got the coach. Did the exhaust from the headers back through Flowmaster 70's all 2.5" pipes.
The radial tires are new on the back and about two years old on the front. I keep close watch on tire presure.
I just got my MSD ignition box and will try to get it installed this week. More complete fuel burn may not translate to better MPG but I feel better if I'm not dumping raw fuel out the tail pipe.
I drive with a pilots instrument scan, don't even realize I'm doing it most of the time, and one of the critical gadges is the vacum gadge.
Last economy check was on the way to Florida. Tank included a few days around town (50 miles) and then 62-67 mph down I-95 into Georgia. Generator was running at close to idle with computers running and the total worked out to 9.44 MPG. For a 28' gas unit I'm very, very, did I mention very, HAPPY!
I figure without the generator running the coach is getting close to or topping 10 MPG. As I'm on the road daily this is the most important part of my overhead. What I spend on fuel economy improvements I hope to put into my bottom line... eventually.