Some recent updates on the carb and coupler and header...

The static nipple on the carb plate - with the attached fuel tube run inside the fuse - totally elminated the engine sagging (nearly deadstick!) issues when doing outside maneuvers. No change in engine performance at all with the static line installed.

Re the coupler: My max rpm's went down steadily, to the point that the engine was only capable of making 6800 rpm with the 18x10PN. So yesterday I cut the coupler and found that the coupler tape under heat and pressure was somehow rumpling up and constricting the exhaust by about 40%. I didn't have a camera and forgot to keep a piece of it to photograph, but after changing to a piece of Teflon tube the rpm's went right back up. Unfortunately, the Teflon tube I used was not the correct variety and it burned out after a quarter tank of fuel, but at least I have identified the culprit. Unfortunately (further!) the piece of Teflon I have is 5 feet long, so I now have about 4' 8"that I will have to find other uses for. Probably OK for glow, so if anybody has a glow engine and needs some 7/8" ID Teflon, let me know and I'll send you some.

The tape is fine heat-wise, so my back-up plan is to use a piece of aluminum tube between the header and pipe and then wrap it with the tape. This will prevent any constriction of the tape and should solve the problem. I still have the 7/8" aluminum wing tube for the Focus, so I know what I'll be using for that job!

The header bolts are holding up absolutely perfectly with the method I used of drilling the bolt heads and making a big clip from 5/64" piano.