After putting the T-quad back on the 400 in my 73 NY I'm getting a surging/erratic idle.

The car ran great with a 670 Holley but I wanted to give the t-quad another chance after it started spilling gas out of the vents 2 years ago. I put a kit in it and adjusted everything as per the instructions and tips I read from Demonsizzler.

There is no bog and it goes down the road fine, but the idle is all over the place revving up and down on it's own. It might be fine for a minute or so then it will start slowing down and almost die, then it kinda fixes itself and speeds up a little and repeats the cycle. If I crack the throttle to say 1500rpm it's ok, but it doesn't like anything under that.

The idle mixture screws are about 2 turns out, but messing with them didn't seem to make much difference. Because of the surging idle vacuum is going all over the place from 12 to 15 or so. It's a steady 20" at 1500. The exhaust sounds choppier than normal as well.

It's a low comp 400 with a lunati 60302, timing is 18 initial, and 36 total.

I'm not ruling out that it's something else though.