Fine Tuning a 360 Magnum with a Brawler "Double Pumper"

Hi all,

First time posting on the forum, I was posting on DodgeForum but was pointed here by another member as the first gen Dakotas are mainly EFI, and this forum has more knowledge on carbs. I've been chasing a couple of issues but wanted to get some final input to help me fine tune my carb.

For starters, I have a 1992 Dakota with a 5.9 out of a 1999 1500 mated to the stock 5 speed. Edelbrock Performer RPM Air-Gap, Brawler BR-67276 Street Avenger Mechanical Secondary 650CFM carb, Comp 20-745-9 cam considered a "towing cam" for the 5.9, JBA shorties, and then just the stock y pipe into a flowmaster super 44.

Timing is about 14 degrees, and I currently have #66 primaries, I swapped the secondaries to #71s but I'm not really worried about the secondary circuit right now as I really don't get into it too much. Stock had a #71 primary and a #74 secondary. Still have the stock 6.5 PV and stock accelerator pump nozzle. My current list of issues are as follows:

- Cold starts are extremely rich and it backfires during high idle (I can hear faint popping from the tailpipe, this is a new issue.)
- I have to let the truck warm up for at least 10 minutes before I can actually drive, and I don't mean comfortably I mean it will not drive if I put my foot down at all it will stumble, backfire, or die.
- It has a sometimes really bad off-idle stumble, sometimes it just will fall on its face, sometimes it will backfire through the carb.
- It smells rich and tailpipe is black after cruising.
- I'm trying to break the 10mpg city driving line, this is a "daily", not a race truck lol.

I currently have a size 35 pump nozzle (bigger) and a 9.5 PV on order to experiment with, as well as #64 jets currently on hand. I did put the 64s in but I felt what I would guess is lean surging while cruising at moderate throttle in a high gear at low rpm, which is part of the reason I ordered a 9.5 PV.

This engine is very vacuum happy, at least from what I've read about other SBMs. A little over 20 inches at idle, cruise is about 16-18. I know there is a lot of controversy about how you should pick your PV size but I feel like 9.5 is a good size for my setup because while experimenting with vacuum, I rarely if ever dipped under 7 inches under normal driving conditions. Right around 9 is where I can hear the engine kind of surging and if I give it a bit more throttle but don't open the secondaries it really starts to choke. That's the thing that got me thinking I should buy a 9.5 PV.

Of course the best way to tune the jets is with an AFR gauge but until I install one I've been reading the plugs and I guess smelling the exhaust but thats not exactly accurate lol. The plugs are brown, not wet, but I feel like I can get a little lighter brown on them while still being in the safe range. Just wanted to get some input from you guys to see where I can focus my attention. This is my first carburetor so I'm still learning all the bits and bobs. I know this is a forum for A bodies but I feel like the knowledge will still be pretty useful to me, and honestly I wouldn't be surprised if the weight between a Dakota and an A body were close enough where technically its "the same" in the eye of the engine.