gas tank swap

[ruquickr67]

need help and info on what is the best and cheapest way to swap out the gas tank on my 86 shortbed stepside? would like to put the tank in the rear between the frame, just not sure of what will work. thanks

[Russell]

Best and cheapest is a stock K5 32 gallon tank!

Here is how I did the swap on my truck, except I used a 43 gallon Suburban tank on my longbox fleetside:

http://www.captkaoscustoms.com/blazertank.html

You'll notice that if you keep your tank full, your truck will ride nicer, and even stop better with a bit more weight behind the rear wheels. I know my stepside always locked the rears up way before the fronts, and almost got me into trouble a few times...

Toughest part of the whole swap is routing fuel lines, and figuring out a filler neck. Filler neck should be reasonably easy with a stepside though, just shave the marker lights, and swap the fenders around, should put the fuel fill at the back of the passenger side of the truck, right where you want it

[ruquickr67]

so the tanks are off of a blazer? and of the same year as my truck? thanks for all your help

[Russell]

Any K5 tank from 73-86 will work fine for your swap. In 87 the K5s started getting fuel injection, and have pumps in the tank.

Some Suburbans got the smaller K5 tanks, and likewise, some K5s got the big Suburban tanks. You'll want the smaller tank for a shortbox. The big Suburban tank just barely clears my diff at full droop in my longbox

[ruquickr67]

I know I am about to sound dumb here, but when you say the smaller tank, would that be the 25 or the 31 gallon tank, cause you also mentioned the 43 gallon tank----thanks

[Captkaos]

That's my write-up, so yes, it is the 25gal tank for the SWB.
I wasn't sure if you were asking or not, but the pickup tank and the Blazer tank are not in any way simular.

[ocbaud]

OR you could do the fuel cell like i plan on doing

http://73-87.com/7387garage/chassis_...ellinstall.htm

[Duro5341]

If you have a LWB, do you still have to move the rear frame support?

I am thinking about this for my 86 K10

Thanks
Duro

[BaddBusa2005]

sorry to bring this back up, but i am looking to do this swap to my truck. The only tank offered is a 31 gallon for the k5 and jimmy? I am needing an 87 an dup tank for the FI. Will the 31 gallon tank work on my shortbox?

[Captkaos]

Originally Posted by Duro5341

If you have a LWB, do you still have to move the rear frame support?
Duro

Not necessarily, but you need something to secure it and flipping the rear support on the SWB provided the same kind of retention as the rear of a Jimmy/Blazer. If you don't move it, you will need to build something for the tank to be pulled up against on both ends.

Originally Posted by BaddBusa2005

sorry to bring this back up, but i am looking to do this swap to my truck. The only tank offered is a 31 gallon for the k5 and jimmy? I am needing an 87 an dup tank for the FI. Will the 31 gallon tank work on my shortbox?

I can get you a new 25g EFI tank, they are still available. I don't quite remember, but the 31g is taller if memory serves me correctly.

Originally Posted by Russell

The 31 gallon is the smaller tank, and will fit nicely between your frame rails

The big one is 43 gallons, which I put in my truck, and that is very tight squeeze on a longbox...

The 25g is the smallest tank, standard on K5's. The 31g tank was standard on Suburbans, optional on k5's. the 40g tank was optional on Suburbans and it is HUGE, it won't fit in a SWB.

There is no 43g tank, all capacities are approximate also.

Originally Posted by benoit454

I would like to do the same thing, but don't you have to remove a crossmember or something and maybe cut the bed sill?

I don't want to cut up the frame or move a crossmember because I have no acess to a welder. Any help? Do I need to move a crossmember or anything? Mines an 84 swb fleetside?

On a SWB you need to flip the rear crossmember around to give a place for the tank to pull up on. We welded a brace across the back to make sure nothing moved when we removed all the brackets behind the rear. Techinically you can cut a piece to fit and use some existing holes, leave the spare tire support there and then removed the rear support, flip it around and bolt it back in (that is what I did in my above writeup) then remove the spare support and bolt it in, make an angle for the strap tension and your done (with the mounting that is).

[BaddBusa2005]

Originally Posted by Captkaos

I can get you a new 25g EFI tank, they are still available. I don't quite remember, but the 31g is taller if memory serves me correctly.

Chris,

If you get a chance will you price me a fuel injection 25 gallon tank, and straps?


Thanks,
Ryan

[Russell]

The 31 gallon is the smaller tank, and will fit nicely between your frame rails

The big one is 43 gallons, which I put in my truck, and that is very tight squeeze on a longbox...

[boatpuller]

i got to do something too.i just stopped using the passenger side after i ran it dry for leaks.i don't drive mine too much or to far.so,16 gallons gets me around.but i remember when gm just about lost the farm over these tanks.so when i do something it's going to be like russell,and chris's write up did between the rails.25 gallons would do me fine.

[Pyrotechnic]

Originally Posted by boatpuller

i got to do something too.i just stopped using the passenger side after i ran it dry for leaks.i don't drive mine too much or to far.so,16 gallons gets me around.but i remember when gm just about lost the farm over these tanks.so when i do something it's going to be like russell,and chris's write up did between the rails.25 gallons would do me fine.

You mean back when NBC Dateline strapped fireworks to the gas tanks to ensure that the gas would ignite and tried to put GM out of bussiness?

[benoit454]

I would like to do the same thing, but don't you have to remove a crossmember or something and maybe cut the bed sill?

I don't want to cut up the frame or move a crossmember because I have no acess to a welder. Any help? Do I need to move a crossmember or anything? Mines an 84 swb fleetside?

[Russell]

Ah, cool, had no idea there was a smaller tank than 31 gallons I know I've got the BIG burb tank, which will cost me like 150 - 160 bucks to fill, and yeah, just barely fit on my longbox, but I didn't know the exact capacity of it, lol

I'm thinking I might ditch the burb tank though, its a real hassle to try and install a fuel door in the rear for the tank, and no nice way to get around it as far as I can tell

[BaddBusa2005]

i am going to put a billet door recessed in the bed side

[Russell]

The biggest problem with that is you have to cut out a square in the inner box wall, and some out of the floor as well to get the filler neck high enough to make sure the fuel pours down and into the tank rather than straight back out the filler neck, lol :d

[BaddBusa2005]

Originally Posted by Russell

The biggest problem with that is you have to cut out a square in the inner box wall, and some out of the floor as well to get the filler neck high enough to make sure the fuel pours down and into the tank rather than straight back out the filler neck, lol :d

well that would be a problem