By choke on, do you mean is it stuck? Don't think so because it was warmed up and running fine in 1st-3rd. It did bind and stick closed once after the install, but would not start and stay running until manually released. I will check first thing in the AM.
Traveling on level ground, paved and not towing.
No cat, removed by previous owner. Just a "glasspack" type muffler and pipe exiting out back at normal location.
Not sure about compression.
Is the vacuum advance controlled by the vacuum line running from Weber to distributor? If so, previous looks at the vacuum line seem good, but I'll check tomorrow.

Thanks