Fuel Tank - Interchange
 

Ive been thinking, on a swb flareside truck, they had a 16 gallon saddle tank. I installed a larger 19 gallon saddle tank on a truck like mine just was a long wheel base.

When I did the install it looks like the saddle tank mounts are spaced the same.

Is there any reason why a 19 gallon saddle tank wont fit in place of a 16 gallon saddle tank?

I got to drop mine to pull the sender as the float sunk on it. Been thinking of upgrading to a 19 gallon tank if at all possible.

I have never tried it, but I always thought they put the 16 gallon side tank on the short bed trucks because there was not enough room for the longer tank. If I were modifying one of these trucks, I think I would go to the rear tank and get rid of the side tank. You could then run the exhaust system down both sides in a more conventional manner. I think I am going to do this on my diesel.

No, they're much father apart on the long wheelbase trucks. The 16" difference between a 117" truck and a 133" truck is between those saddle tank mounts. The front "Mount" is actually the rear cab mount crossmember. It's in the same location on both wheelbases. The rear tank mount is what changes.

Ah ok, I was wondering cause the long wheel base truck I put the tank in at work it didn't look like the mounts were further apart but I didn't measure them either.

I did try a 19 gal in the place of the 16 gal and it would not fit as there was not enough room.
I don't remember now what all was the issue but did not look like there was an easy way to fit it.

Now someone posted to move the rear tank support it would fit but I am not so sure.
Would also need to check where the filler hose will end up at. Is it the same from the end on each tank? Again I don't remember when I had both side by side but a guess they were.
Again if that is the case and the front of both tanks are in the same location then the filler on the 19 gal tank would be back farther and would not line up on the flare side filler door.

My fix on needing to hold more fuel was to install a 19 gal rear tank from my duel tank parts truck.
Now I used everything from the duel tank parts truck to make this work. The hardest part is the main wiring harness as they are different but there is an easy work around.
Use the early 80's switching valve, 2 ports in & 1 out and an aftermarket switch or a mid to late 70's fuel tank switch with under dash bracket.
Run wires as needed to switch the valve and the fuel senders to make the gauge work right. I did this on a 76 E350 van I added a 2nd tank to and it worked great.

Heck I guess you could get the stock fuel tank switch and HVAC panel and wire that switch up to work and look stock like a duel tank truck would just need to make your own harness is all.
If I ever find I still don't have enough fuel between the 16 gal side tank & the 19 gal rear tank I will go with a 38 gal rear with the 16 gal side tank and find a place to mount the spare tire.
Dave ----

I don't know if I will need extra fuel. Once I get the engine built and tuned I will know better what my range is on a tank. I just figured if I am dropping the tank again I might as well spend $120 for the 19 gallon tank if it would drop in easily.

If I did add a rear tank I probably would take and get the lmc rear tank that is 38 gallons.

Are you still going with the 302?

I managed to get 18.25 MPG with my mildly built 302 last summer. That's with a Holley 4bbl, Comp Cam, Edelbrock intake, GT40 heads, and BBK shorties. And that's in my 84 2wd Flareside with an M5OD 5spd. I did hit 250 miles range on a 16 gallon tank last year...I forget how many gallons it was exactly, but around 14.

I think I could squeeze 20 MPG out of it with a few more miles on it, and a little tuning. Cruise control would help as well. With the truck being so light, the 5spd and 3.08 gears make it want to fly on the highway.

One other thing to consider is that a shorter fuel tank may have been used on the shorter wheel base for a safety reason. Having some shy room between body and framing members allows for some crash deformation while still protecting your tank. Bigger is not always better.

BB2

Do you need to drop the tank? If so and you have that old 19 gal one see how it will fit.
As I said it was not a bolt in so I gave up and did not look deeper into what was needed to make it happen. This way if you find it is too much work to mount the 19 gal you have not laid out any $$.

I think even if you get the tank mounted the filler will be to far back to work with the stock flare filler door.
I did not even think of this till yesterday when I posted it as I did not have the bed on the truck at the time.
https://cimg8.ibsrv.net/gimg/www.for...24e2c791e0.jpg
Now you can see them side by side.
If I need to replace the rear tank I will also go for the 38 gal but the 19 gal was free with the parts truck. }>

I don't think that was even thought about. As you can see it was just too big, think the front hit the trany cross member if lined up to use the rear mount and if you moved it back the filler is an issue.
Dave ----

Looks like the mounting is different too...and no room makes it a no brainer. If it were me I'd stick to the 16 gallon. Then if I needed more range on occasion a 5 gallon Jerry can would be strapped into a bed corner. Or as has been mentioned a rear tank could be added, especially if there is a filler door for it and you have all the switches and valve worked out.

BB2

I just did a quick "hold the tank in place" to see if it would fit and because it was not a bolt in I just went back to the 16 gal tank.
As I look at the tanks now if you were to move the rear mount back so the front of the 19 would clear, the filler would now be an issue.

A rear tank is not that hard to install. You can use every thing from any rear mounted tank truck. The front cross member the tank straps go to is different than the non-rear tank trucks so make sure you get that also.
I also do not think it is that hard to do the valve / switch / gauge part and would not need to use factory parts other than the 3 port valve (on a non-return fuel system).

I also don't think the filler door is all that hard to do but that's me }>
Dave ----

yep will still be a 302, well a 306 as I am getting a 306 short block from Blueprint. Power Train Products they went from $2,700 with freight and core for the '96 explorer long block to $3,500 with freight and core but they also changed the warranty and told me under the new warranty the base line warranty wouldn't even cover this engine as its not installed in the application its listed for. Cool guy I talked with on the phone from there recommended I either go with a cheaper engine he has for $1,500 and then later on upgrade the heads and cam. I say screw that.

So I am looking at the 306 short block from Blueprint for $2,420 with freight, going to call before I order to verify it will be 9.5:1 compression with 58cc heads, im looking at AFR Renegade 165cc heads with 58cc chambers, 1.90/1.60 valve, and the Crane Truckmax cam #449541 with specs of 216*/224* @ 0.050, 0.52"/0.542" lift, 112* lsa and 107* intake center line.

That coupled with shorty headers, 600cfm summit 4v carb, edelbrock performer intake, and 1.6:1 scorpion roller rockers, I think with everything properly set up should net me easily 300 - 325 hp. DD2000 is estimating 376hp @ 5,500 rpm with all the specs put in including flow data for the AFR heads and selecting short tube headers with muffler.

I figure 300 - 325 would be a good estimate for this.

I do plan on using my 02 sensor with my air/fuel gauge to try and tune the carb. I think I want to try and tune it to be around 16:1 lean when cruising with no load to try and maximize fuel economy if I can get it that lean I don't know. Under load I want to shoot for around 12:1 to 13:1 for the rich side as its supposed to be the best power range from what I read.

Not sure if I can possibly get it done but I got to find out what jets this carb takes and get an assortment of jets I already got a quick change secondary spring kit for this carb to install as well. Im also looking at recurving the dist I got a Crane vacuum advance kit that comes with springs and a adjustable vacuum advance. Engine builder I know swears up and down by pinning the plate to stop the vacuum advance from pulling more than a total of 32 - 36 total advance mechanical with vacuum.

On the ford muscle forum they are saying 32-36 total mechanical advance and let the vacuum go where it wants with in reason.

Currently my stock 302 with the 2V carb with my slipping C6 transmission I was getting about 12 mpg city. Once I get the engine done and have the C6 built throw in the hughes tow converter, the wide ratio planetary gear set, the truck/rv shift kit that should help my economy some by eliminating the 10-12% slip my C6 has currently. Then the 3.25:1 currie third member with truetrac for $1,700 im looking at should help the truck turn those 31" a/t tires easier so that should in theory help my economy out as well. Since I am possibly looking at having to run straight 93 octane with this setup with aluminum heads and 9.5:1 compression I don't mind if I get 15 mpg highway but I would like to get up to around 18 mpg since most of my driving is going to be 65 - 75 mph on the highway and nothing will be close to me after my move.

That is why I was really contemplating the 19 gallon saddle tank. But since I have no use for the spare tire, I would consider the large 38 gallon fuel tank LMC offers if it will fit a flare side with a wood bed. If so then I might consider doing something with a filler door in the wood bed to fill the back tank up.

how are you planning on doing your rear tank fuel door? Going to cut the fiberglass fender and mount another flare side fuel door on the back side of the flare?

I don't know if I would want to do that. I hate the thought of cutting new stained wood to put a access door but I also hate the thought of cutting the fiberglass fender to add an extra filler. not sure how it would look is my big thing. Don't know if it would look right or look weird on such a short bed truck.

Yeah...I love my new plastic rear tank sitting up on skid plates...:-jammin

Filler door...well that's an art for sure. I'd probably cheat and cut a filler door off a donor and then cut a hole in the side of the receiving bed and weld it fill and fair from there...I think. Maybe there are other ways...but that's your thing for sure. :-X22

I might be inspired to do some body work on my truck after seeing some of the stuff folks do here...but I am still a grasshopper in the world of body and fender.

BB2

Not sure I would call yours mildly built :p you are pushing a 1HP per cube, well over twice the HP of stock.