"truck runs pretty good i'm just not that up to date on all the computer stuff nor do i have the budget for it "
Than just leave it alone, there is no cheap & easy way to convert, the ECM also ties into the 700R4.
IF you can find a pre 87 Astro van with a 305/350 & 700R4 with a non-electric carb, grab it up for the parts, harnesses and ECM and plan to send a week changing things over, then pray for the best.
Changing over to a CCC carb makes no sense, just as much computer control and more expensive. For giggles I just checked NAPA for parts:
a Holley rebuilt E4ME Q-JET is $700
Echlin rebuilt parts for mine is $250 + a weekend tinkering around
off-brand parts are $150 and questionable
This really does sound like an idea that should die on the vine, sorry.