Im having some trouble with timing my car. I have the MSD 6al box, blaster 2 coil, and MSD pn 8361 distributor. When my car is idling (900) my timing says 27* with the vac advance disconnected. It seems to run fine like that. But it shouldnt be that high so i try to bring it down to 10* but then motor runs weird. I will tap the gas and the rpms will go up way to easy. Can anyone help? Thanks

 

You should be able to lower the idle speed below 900RPM... Also, 27*, with that cam, and your compression ratio and whatnot, sounds fine. More duration needs more timing at idle.

Which springs are in the distributor? Maybe the advance is coming in at idle, making it unstable.

Are you running manifold or ported vacuum advance?

Then finally, shoot for ~32* timing at 3500RPM. Adjust for that. Then bring it back to idle, and let it be at that timing. Use manifold vacuum advance timing if you need more timing at idle to get it to run right.