so, if you plug those two ports, it runs ok, but if you hook either up, it races? sounds like maybe you're hooking up a leak.
if they're not hooked up, and not plugged off, it should be racing due to a huge vacuum leak. plug one off, start engine with the other leaking, and then hook and unhook the hose and listen for any change. do the same for the other. if there is no change. ether the hose is not hooked up on the other end, or what tis hooked to is leaking. i hope this helps. its difficult when i'm not there looking at it. i'm assuming you have auto trans. if not, just keep that bottom port plugged.
it could be you have a bad diaphragm on the dist. advance.
actually, now that i think about it, that timed spark ign. port should not be drawing much vacuum with your throttle plate closed. double check your idle screws and make sure choke is open when you do all this.
i guess i'm just telling you stuff you already know, but keep us informed, with details.