Quadra Jet, ign timing and Pontiac 400

[53 Chevy5]

Here is what I got going on. It's my 77 T/A of course ( turns out it's not a 78 ) . It's been too long to remember what I did to the inside of this engine but I do know I put in higher compression pistons to increase the factory 8.5 and I did install a healthier cam. I do not remember the details of either which will make this a bit of a guessing game but the rest is stock. Seems like I can't get enough vacuum, a shaky 15 at best and I also can's seem to get my Idle low enough after it's warmed up, it stays at about 1000.When the A/C kicks on it about kills it then comes back and generally everything is just a bit erratic and doesn't react to adjustments and the motor doesn't seem to pull like it used to ( not 100% sure about that though). The base timing is at about 10 deg and hooked to manifold vacuum, total advance seems a bit high at 38 deg. A lot of this points to a vacuum leak but I can't find anything. I screwed around a lot with this engine when I was younger and I think now I'm paying the price.