Has the motor jumped timing?

A couple of questions on timing and carburation.
1986, 1/2 ton, /6, automatic Truck stopped running had no spark we eliminated the computer and set up a GM module with the ecoil. Reset the plug gap to 45. The motor will not run unless the timing is set to 20-24 degrees btdc. Even then it has a miss.
When I set the idle to where it would start and run it wants to run at 1500 RPM or more. And then the next time I start it it wants to idle at about 800. The carburetor is junk I would like to replace it with a non-smog carburetor. What are thoughts on that.