95 4.3L Step van swap for a 94 GM 30 HD Van 7.4L Computer

[bobx]

I have a 95 Utilimaster Step van, P30 chassis with 4.3l v6 and been offered a 94 gen V 454 on propane... and everything from it needed to swap into my V6 van.

Looks like the same wiring harness and motor mounts, anyone know if the computer is the same between the V6 and V8, and or need to swap the computer and likely also has the same harness to ?
This the 30 HD chassis with bigger 19"? wheels straight axle front end and flip hood, regular van cab. and 16' box, Might be a beefed up version of the P30 or other P chassis. ?....has overload springs, my van doesn't but with the V6 still has the same big transmission and straight axle front end with 16" wheels.
The propane engine probably has something to bypass some computer controls or wiring not required for propane, but I'm thinking of staying on gas...till I get all the stuff needed for it to pass inspection, run on propane.
It has some kind of alternative fuel management module on the firewall, but looks like it hasn't been used for years and no wiring harness to it so might have something else elsewhere..

The big block sits a little more forward on the motor mounts with extra piston bank so just a little closer to the rad, uses the same transmission,
Looks like a straight bolt in and probably still use the V6 air cleaner intake and all the same wiring to the sensors etc., looks like the same TBi on it but with a propane mixer on top and possibly reuse my V6 TBI, ? better fuel consumption ? otherwise the V6 is also a pig on fuel, the big block might not burn anymore and eventually end up on propane anyway....or also wood gas.

My van also seems to be missing the diagnostic terminal....or isn't anywhere obvious inside the cab or anywhere they might normally be, does have what looks like a missing plug on a piece of wiring harness under the hood.....I yet to trace back..... When the check engine light used to come on, no way to read codes....

Thanks, bobx

[joecar]

So what is your EFILive scantool/tunetool/V1/V2/V7/V8 question...?

Seriously, you don't state any specific question(s).

[slows10]

Looks like to me his question is in the first sentence of the second paragraph.But could be wrong? Op what obd1 ecm is in there now?

[joecar]

Looks like the same wiring harness and motor mounts, anyone know if the computer is the same between the V6 and V8, and or need to swap the computer and likely also has the same harness to ?This...?

[bobx]

Sorry I figured it would be at least evident with the subject being swap and 2 different engines....and describing the differences.
I'm speculating the V6 p30 and 454 30HD are near the same platform...as opposed to a regular style passenger or cargo van,

I'm presuming my Van and the other is OBD1,..and is a TBI engine as opposed to the later style injection and distributor.
I'm missing my diagnostic terminal....or isn't where normally, Utilimaster doesn't have any info going back that far and suggested if not where normally above the gas pedal, (Like my cars's) or better place by the open fuse box on the drivers side of the dash and can see the computer behind it.... might have to take the dash apart to get at??!!,
There is chunk of wiring harness under the hood that looks like it's missing a plug I yet to trace....

Somewhere I found it noted that TBI 454's used a different computer for 94-95, but how far off are the computers between the V6- V8 350's and 454's normally... The 94-95 computer apparently marginally different, But concern was different enough to also need the dedicated wiring harness to swap the 454 into my originally v6 equipped van.... and maybe not require it...
I did find out the 454 uses a bigger TBI....but also wondering how it might run with the V6 one....

Other concerns were retaining transmission control without having to buy a 3rd party controller for it or hacking it manual.
It suggested when doing a propane conversion the injectors and fuel pump is just switched off and the computer doesn't know any better or creates a code that there no fix for and runs anyway.... Can't seem to find much info on that either, but some on the unused fuel management module the 30HD has but manufacturer no longer supports or exists....

When I had problems with the V6 TBI and couldn't find the diagnostic terminal to generate a code I was looking into converting it to carb and HEI....but that creating problems with the transmission and other functions going computer less....