Valve lash compensation

It idles at 800 but were using the vac can on the distributor to bring up the initial timing. It has a FBO restrictor plate in the distributor, without the vac it's 12 initial, with vac it's 30 initial. total is 34. No vac to distributor at 800 it's unstable at about 10 for vac, things improve with the vac hooked up to add advance. Static compression is 10.93 to 1