454 carb thunderbolt IV... timing all over??
 

I set my total advance at 34 degrees...... after around 4000 the timing jumps all over the place, I cannot remember if this has done it with multiple boxes since I have so many different issues to figure out....I have new coil, and new pick up, I am trying to find another ingnition module but I swear it did this with 2 different ones......

I am also thinking of ditching the merc ignition and going with something else....

What would be any other suggestions? this engine is very sluggish to go from 4500-5000 takes a minute catch up... does not feel as strong as port goes right to 5000

The timing should not jump around at all. Sounds like a bad connection or ignition module. Swap them from side to side.

I run new small module on that engine, a old box on other one, I have a buddy with a few extras, I plan to grab one from him to use..... the connections are good as well as I ran new ground from battery to be sure...

Is the rotor tight to the distributor shaft?

I will check that didn't think about that

I Agree. If that checks out I'd also take a peek at the distributor gear.

I may just buy the msd distributor and drop it in...