Bad fuel pump, restricted fuel supply, rusted tank particles blocking the
fuel pickup?  I think it's a 36 gallon plastic tank though, maybe the "sock"
has crumbled restricting the pickup?

Check your timing chain for wear. It shouldn't have much more that 10
degrees of play in it.

Denny

Hi Russ !
            looks like we have similar situations, I to have just bought a
1978 Dodge tradesman B200 (class B motorhome)with a near mint state body
wise and 86,000 km on it. But mine is a 5.9 Litres 360 hp with a double
barrel carb.
Mine also starts instantly and runs smooth until I depress the
accelerator......then it chokes and dies on me if I dont decelerate, it seem
to refuse to take the effort to accelerate straight down to the floor.

I have checked for proper firering order, checked the distributor cap and
componets inside (rotor & stator) I have a Haynes Dodge and Plymouth vans
1971 thru 2003 repair manual not the best apparently but its the only manual
I could get my hands on fast, since I am not a mechanic I just hapenned to
check out this newsgroup and found you and your situation.(similar to mine)
!

I will check on the gaz pump like John mentionned and the timing chain like
Denny mentionned, but it will be sometimes this coming week before I get
back to you guys on the results. I have found a Chrysler mechanic that works
exclusively on  Chrysler motors (he work at a Chrysler deaslership) and
helps poor guys like us that hate paying for dealership exorbitant hourly
pricing rate.

Looking forward to find a remedy for our situation......in the meantime its
nice reading that I am not the onlyone with my problem.

Regards ....J-P.