Thanks for the input Guys.
So... let me understand this...
I can use either of the TBI units I have with similar results, but need a different ECU to control the 4L80E?
Reading the responses... I "could" fit either and "update" the system later?

My bigger issue is the smog... everyone I am in contact with tells me that the original Quadrajet, barely passes smog here... it just cant control the mixture as well as an injected motor. My 87 suburban ran like a top, blew thru every smog test with its replacement Magnaflow cat and catback system.

It is my understanding that I will need to retrofit every item from the correct model year to have it inspected and approved by the "Smog Referee". After that, the vehicle will be judged by the smog rules as "a 1987 Suburban R2500" for example.
My issue is deeper, so I need to go slowly... t
To retrofit this I need to do not only the TBI/electronics/evaporative system, but also the smog pump/alternator/AC compressor/brackets/belts/pulleys as the setup is different to what is on the Motorhome now. The '84 smog system was all mechanical/temp/vacuum driven.
The '87 has a odd hybrid belt system, with wide serpentine belt driving the fan/smogpump/alternator, and V belts driving the PS pump and AC compressor.
If I use the stuff from the '90, it gets worse or better... and that has a single serpentine driving it all, but the waterpump is reverse rotation... and I am not 100% sure I have every single component I need.
Advice of thoughts?

Pulling out the 80 gallon tank for a clean and seal is on my list, so I will probably use an in tank pump.. I will have to look at what I have for a return line, and maybe add something.

From what I understand, Banks Power system for that period 454 was a kit that comprised a tall cast aluminum airfilter housing, a pair of long tube headers, and single free flow exhaust system.
They claim it adds almost 80hp, and 100ftlb over stock.
http://bankspower.com/products/show/...20-%207.4L%7C1

After my drive back from KS, I notced that the Banks Airfilter had been replaced with a "performance" pancake filter... that's what it needs... to ingest hot air from under the doghouse! Agh.

I was lucky to find the shabby looking Banks unit in a storage compartment, and after some work, and a finding the correct OEM lower, it looked ready.


If I do this swap... can I expect any performance/economy gains?
Any advantage in using an Edelbrock TBI intake manifold over the OEM intake?