Sometimes when you make improvements to a vintage vehicle, the results become a self-fulfilling prophecy. And sometimes you actually have evidence that there has been an improvement. So it was with two small things that were done to make the van a little more fuel-efficient and quieter at higher speeds. The first change was the air filter mentioned in a previous post. However I also added some seafoam to the next fill up of gas. Between those two changes the next full tank of gas resulted in mileage of 13.6 miles per gallon. This is up over a full mile per gallon over the last tankful with similar driving. This is not a big enough difference to declare a full cause-and-effect, and it was not a scientific experiment, but I'll take it.
The second change was the replacement of both belts in the engine compartment. Both of the belts looked like they were in fairly good condition, but I was chasing a squealing sound that occurred once underway for about an hour and at speeds over 75 mph. The replacement of the belts is fairly straightforward with moving the alternator and the steering fluid pump in order to remove the belts and put the new ones on. The result on a test drive was no squealing at higher speeds. A full honest test of this will be a lengthy trip with speeds in that region to determine that it is truly solved when the belts and the engine are hot for some time. But for now, I'll take it.