carb adjustment

Probably no need to adjust the timing, if it is set reasonably (10-15 degrees static, 34-36 total). Just make sure everything is up to snuff. Fix any possible vacuum leaks. Don't start second guessing things, and don't change more than one thing at a time. A bog can be caused by several things, but start with the carb since your ignition system sounds to be OK.

First, download the Edelbrock manual for your carb, read and heed.

Next, start out by setting the carb to the factory baseline. (For an Eddy 1406, thats .098 primary, .095 secondary jets and a .075 x .047 rod, with yellow 4" step-up springs.) Make sure the float level is correct (11/32"), accelerator pump is in center hole, and make sure you have a good fuel pump and a new fuel filter. Disconnect the vacuum advance hose, and cap it at the carb. Now test drive the car. Better?

Personally the next step I use to dial out a bog, after setting everything back to stock, is to REDUCE accelerator pump shot (outer hole on an Eddy). This should make it worse, verifying you are leaning out. More than half the time I have found that people set the accelerator pump way rich and the overwhelm the ignition system with fuel, especially with Holleys.

If you do want to play with the timing, and by all means do so, try advancing 5 degrees. Unless there is a HUGE improvement, that wasn't the problem. Get the carb right first, and do not change more than one thing between test drives.