Is there an after market that will pull more than the factory water pump mounted fixed fan?

Not sure what your combination is, but I've cooled some pretty "hot" motors with stock stuff. Fan shroud is the biggest deal, worth 20 degrees or more. On a couple of cars, using a smaller fan pulley sped up the fan enough to make a significant difference.
I consider 180 in traffic on a 90+ day the max temp I want to see.
OEM fan shrouds for 22" radiators are rare & spendy, but if correct appearance isn't important, later plastic shrouds can be adapted. Also, Speedway in Lincoln, NE sells a universal shroud that fits a 26" rad pretty well but you have to fab brackets.

More info on what is going on, what pump (# of vanes/anti cav plate or not) how many fan blades. what stat. spring in lower hose? Stat opening all the way. shroud or no shroud. timing/A/F ratio in the ballpark. running hot at idle or around town or on highway. how hot. confirmed with an accurate gauge. any recent part/adjustment settings that could be impacting the cooling system (or A/F ratio). recent issue. happened out of the clear blue.

Summer time here of coarse its going to run warm but manageable but when I added the A/C condenser it was to much without the air turned on, the main problem is at traffic stops. 68 Valiant 440 auto 18" 6 blade fan shroud 3" thick 22" Champion radiator Mopar performance aluminum water pump and housing 180 stat

Yes as you surmised you need more airflow. I'm thinking 6 blades is adequate & that the pulley ratio needs speeded up & the fan does need to be properly spaced into the shroud (~1/2 or a bit more in). its tough to get the right pulley with the right depth so the belts line up.

Clutch or no clutch fan?

I was looking for the same answer a little while back

https://board.moparts.org/ubbthreads/ubbt...tml#Post2416262

No clutch, no room. I do have the spring in the lower hose but that is for cruising speeds. Read my plugs and they show a lean condition which equals heat and I'm thinking a header wrap to get some of the heat out from under hood.

I had a problem like yours only my a/c wouldn't work well when sitting in traffic. I have a fixed fan with a shroud. I installed a pusher electric fan on top of the condensor and the problem was fixed. It only comes on when the a/c is on or if I get above 180.

I much prefer the Milodon Water Pump with anti-cav plate to the MP pump, as much as I like to keep things Mopar whenever possible