I've been having trouble smoothing things out with my car after head/cam swap. I set the timing to 6* BTDC with the EST disconnected when I hooked it back up the mark was bouncing all over the place while idling! and when I revved it it would smooth out but the mark would be very very advanced. another thing is that it would not rev over 2500 rpm? any ideas as to what's going on? I'm guessing this has something to do with the computer cause things seemed alright with EST disconnected; I haven't check for any codes yet though. car is a 350 TPI

 

There are a few things that can cause timing to jump as you described.

The distributor gear not shimmed properly

Distributor with worn bushings;

Loose rotor;

Worn timing chain with too much slack;

Roller camshaft not installed with thrust bumper and Torrington bearing and

A vacuum leak.

Did you remember to clear the error code after setting the initial timing?

Are you getting any other error codes?

Jake