Just a little miffed...

Is the heat riser butterfly open/ opening?

Have you run compression/ leakdown tests? If you don't have a leakdown tester, Google. They are easy to make, OR you can bring each cylinder up to TDC and simply introduce air. Listen at intake, exhaust, look in radiator for leaks

Run a cylinder balance test. Easiest way I've found is to pull up the distributor boots, and insert small brads down beside the wires into the plug towers. Then just take a grounded probe and ground one at a time, watch a tach or listen. Each cylinder should drop equally

What does the vacuum gauge act like?

Some vacuum gauge pages:

http://www.secondchancegarage.com/public/186.cfm

http://www.therangerstation.com/Magazine/Summer2003/VacuumLeaks.htm