Today I got the Chevelle back from Comp Chassis. It turns out the pinion was several degrees too far down. Hopefully that will banish the last of the vibration.
Also the manual master cylinder is in. The pedal is still softer than I'd like, but Mike tells me it'll go up to 1400 PSI if pumped a couple of times.
I also lowered the hitch a couple of inches, it looks like the weight is almost perfectly split between the trailer axles now.
Meanwhile I've been working on prepping my Camaro for paint. It looks like it'll be in primer for the fall races and will get the base/clear around Thanksgiving, because as always there was more wrong with the body than it first appreared.