So the 4.3 efi fuel sending unit I've been using for the last couple years kicked the bucket recently and while looking into replacing it, I came across the 91-96 Chevy Caprice / Buick Roadmaster Wagon fuel tank swap that some have done on here and over on Gbodyforum. Pictures on the install can be scarce sometimes so I figured I'd be a good member and post up some pics of my install. As others have said, the tank itself is a direct bolt into our cars. The overal size and tank strap locations of the factory El Camino tank and the Roadmaster tank are nearly identical, with the Roadmaster tank being slightly larger on the sides with the increased capacity. The replacement tank straps I've been using with the Spectra tank I was running were a little shorter than the stockers so they snugged up perfectly on my setup. I have heard though that OEM tank straps may be a little long for this tank.
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As with most people who run an EFI setup, I use a -6 size braided fuel line from the tank to the throttle body on my truck and use the factory 3/8" feed line as a return.
![135209]( "135209")
With this in mind I had some slight work to make the sending unit from the Roadmaster work with my fuel lines as the Roadmaster has a 3/8 feed line and a 5/16 return line. I used some Russel quick connect to 6an line adapters coupled with push lock fittings to connect the tank to the lines, connecting the feed line outlet on the sending unit straight to my 6an feed line and then running a short section of 6an line from the return on the sender to the factory feed line hard tube by the frame. I just left the vent tube alone as I don't have any of the charcoal canister stuff anymore as it is.
![135210]( "135210")
![135211]( "135211")
With the plumbing out of the way came the annoying part of the install. I read a thread on Gbodyforum claiming that a Roadmaster sedan filler neck is a better fit for our cars then the Wagon filler neck. My experience was not quite the same as I had one heck of a time getting the sedan neck to fit at all and even then it wasn't until it was "massaged" quite a bit in a bench vise with a sledge hammer to clearance. I'll be locating and installing a Wagon filler neck in the near future and giving that a try instead.
As far as the wiring goes, the harnesses are identical between the two, though I did shorten the harness on the Roadmaster sending unit a bit to make everything fit a bit better under the car.
I can say now that its all done though that its quite pleasant having a fuel gauge that actually reads correctly when filled instead of reading full for the first 100 miles as my old one always did (as I think most of the 5th gens do).
As with most people who run an EFI setup, I use a -6 size braided fuel line from the tank to the throttle body on my truck and use the factory 3/8" feed line as a return.
With this in mind I had some slight work to make the sending unit from the Roadmaster work with my fuel lines as the Roadmaster has a 3/8 feed line and a 5/16 return line. I used some Russel quick connect to 6an line adapters coupled with push lock fittings to connect the tank to the lines, connecting the feed line outlet on the sending unit straight to my 6an feed line and then running a short section of 6an line from the return on the sender to the factory feed line hard tube by the frame. I just left the vent tube alone as I don't have any of the charcoal canister stuff anymore as it is.
With the plumbing out of the way came the annoying part of the install. I read a thread on Gbodyforum claiming that a Roadmaster sedan filler neck is a better fit for our cars then the Wagon filler neck. My experience was not quite the same as I had one heck of a time getting the sedan neck to fit at all and even then it wasn't until it was "massaged" quite a bit in a bench vise with a sledge hammer to clearance. I'll be locating and installing a Wagon filler neck in the near future and giving that a try instead.
As far as the wiring goes, the harnesses are identical between the two, though I did shorten the harness on the Roadmaster sending unit a bit to make everything fit a bit better under the car.
I can say now that its all done though that its quite pleasant having a fuel gauge that actually reads correctly when filled instead of reading full for the first 100 miles as my old one always did (as I think most of the 5th gens do).
