454 tbi into 1972 gmc

[70net440]

Looking at putting a 1989 454tbi/th400 out of a Suburban into a 1972 GMC Camper Special. The 72 currently is a 350/350 air cab. I know we will need big block engine stands and new or modified wiring harness for the tbi. Will the Suburban fuel tank fit under the bed of the 72? It is leaf spring rear. Anything else we may be missing?

[MARKDTN]

Should be fairly straightforward. BB stands and bigger radiator out of the square body, probably the exhaust manifolds will work. The harness is pretty much stand-alone. I don't think the fuel tank will work-too big. You can use an early S10 Blazer tank that fits OK and use the TBI pump in it.

[70net440]

I thought the suburban looked way too big. I think Tanks Inc. makes a Mustang tank that uses a GM sender and internal fuel pump. Are any of the aftermarket engine stands better than the other?

[Greg58]

You will love that engine, great power and smooth operation.
My 87 TBI likes gas a lot!

[rjs53]

Put a gen 6 BBC out of a 96 Chevy truck in a 65 el camino. Changed the cam and pit a carburetor on it, ran like a raped ape, as long as it has gas. The throttle body might get you 10 or 12 miles to the gallon and it'll start easy. No tuning makes it nice

[70net440]

Anyone have a recomendation for headers? Also does this system need a vss?

[rjs53]

I used the headman 1 7/8" full length. They fit good, and had ball socket style collectors, never had a leak. I broke them in per the instructions, which I usually don't follow, and they stayed black for a couple years.

[stsalvage]

the Problem he still will have is its going to drink as much fuel or more using the 454/400 as your 350/th350.My thought on this why not just buy the 6.0 with the 4L80E and get 19-22 miles to the gallon.If you get as much as what the rear gear will give you.In Calif Your not saving your self any problem and the TPI system is broken.

Trying to find a throttle body that dose not leaks air need new brass bushings or the bottom plate is not warped.To me if you where going this rout and you Know are Gas is way the hell out there on price.You get the 4L80E with the Tci harness to get the mileage.

A guy that works with this stuff tells me that's old for gotten technology.Yes you can put up the combo for 1000.00 you can buy a 5.3 with a 4L60E for 1200.00 with 80K on it I'm a bigger fan of the 4L80E

[clay68c10]

You will need a VSS for everything to work correctly. There’s a lot of functions that use it as an input.
The tailshaft on that newer th400 probably does not have a speedo cable output. Those years had an electronic speedometer. Not sure what you are doing for gauges.
I’ve used the type that goes inline with the speedo cable on 2 TBI swaps so far and it works great, but I was using older transmissions.

I think an 87ish full size blazer tank may fit and has the right fuel pump for you. Do some searching on here and see what comes up. Having a long bed makes it easier.

You will also need a Park/Neutral signal to the ECU

[70net440]

Looks like a 87 blazer tank will work. The trans does have a speedo cable Biggest problem is that the donor vehicle might be too nice to cannibalize. We may have to just add it to the heard.