When the blower is on there is not much air coming out of the two side dash vents - I am assuming that these have a vacuum actuated damper? If so, after I check/replace the vacuum hoses is there anything under the dash that I should look for?

 

Yes, they are vacuum actuated. If repacing the vacuum lines didn't fix the problem post up. There are vacuum lines in the dash and connect to the control switch on the dash.

 

This thread includes a schemataic of HVAC vacuum system.Heater help - vacuum

All thanks to Kyle for provide the information in the linked thread.