Distributor won`t advance.
 

I just finished swapping my 310hp 7.4 MPI to carburetion. I used an Edelbrock Air-Gap intake, a Holley 800 mech secondary carb and a Holley "RED" electric fuel pump. I retained the Delco Voyager ignition system that was on the engine.
I have my base timing set at 10* BTDC.
The engine stumbles a little out of the hole ( I think it is in the jetting ). It runs strong through mid-range but starts popping lightly through the exhaust at about 4200 rpm and seems to lose power at this point. I checked my timing with an advance style light and only see 16* from 1500 through 3000 rpm. I realize the ignition module controls the advance, so I purchased a new one along with a new coil, just for good measure. This did not change anything.
Do you think that timing is my problem? I would like to see 30-34* total timing. Am I missing something? What is the correct method to time a Voyager distributor?
The engine has 18" of vacuum at idle. The idle quality seems a little rough as if it has too much timing at idle......???
Any clues? Suggestions?
I just spent a wad of dough converting to a carb and now I`ve run into this!
HELP!!!!

THANKS!!!!!!!!!!!!!

I wanted to add:
The main reason I removed the MPI set-up was because of poor idle and no balls out of the hole. All of that started with the first outing this spring. Maybe I had a bad distributor all along?
I was hoping to see a nice improvement with the Holley.......I need help please!

Does anyone have any ideas on this?
I could really use some advice here.
I`m at wit`s end trying to figure it out!
THANKS!!!