My 78 F150 4x4 needs a new gas tank. I want to go with a larger tank. And I would prefer to go with a plastic tank. So far I've only been able to find a plastic 33 gallon Bronco tank. All the 38 gallon truck tanks I've found are steel.

Will the 78/79 Bronco tank fit in the 78 F150 frame?

 

Why plastic? Afraid of rust? Don't forget, the steel tank it came with lasted 34 years. You gonna own it that long?

The Bronco tanks stick up 2 or three inches above the frame rails. The stock tanks sit flush with the frame rails. You may need a body lift to clear the tank, or just modify the brackets and straps to lower the tank. It should physically fit in the same spot side to side, front to back though. Personally I'd just put the stock tank back. Putting 38 gallons in a tank at once is AWFULLY expensive.

 

Well I live in Minnesota! I've had lots of steel tanks that rusted out and started to leak. Or they just started to leak from the seams. The plastic tank doesn't have any seams to leak. The truck is going to see a lot of winter use and possibly also see some plow duty. I've spent over 5 years building this truck and will probably have another 5 years in it before it's done. So yes I plan to own this thing the rest of my life!

I'm not worried about how high the tank sticks above the frame. I'm mounting a 1954 F100 body on it with a 4 inch body lift. So I should have plenty of room to work with there. I was mainly concerned about the width of the tank. I thought the 78/79 Bronco's might of had a wider rear frame section then the F150.

My current daily driver is a 96 E250 van with a 38 gallon tank. It's nice having the big tank on long trips. For regular daily use I usually just fill it up when it hits half a tank. That hurts a lot less then waiting till it's empty.

 

Oh ok. It all make sense now.

Then yeah, a plastic 33 should fit. You just have to use the skid plate and upper straps to put it in. (Bronco's mount with a heavy steel skid plate from the bottom because it hangs down pretty far.)

The only other criticism I'll offer, is the height of the proposed body lift. I understand it may be necessary to fit the early body on it, but I would try to find a way to lower the body down a bit. While I'm good with a 3" body lift, 4" is starting to put some serious leverage on the rubber mounts. Especially the back and forth, start and stop abuse of snow plowing. ...just sayin'.

 

I should of said the body will be raised 4". I'm making raised frame mounts/brackets and a raised frame crossmember for the rear cab mounts ( using the rear floor section from the 78 to get the rear cab mounts ) . Not using any pucks or body mount spacers. Just using standard poly body mounts. I wish the 54 body would work without raising it at all. But I need to raise it 4" for it to work with the 78's frame contours.

 

Ok good. I'm going through the same thing with a '66 F100 on an '85 Bronco frame. I chose to section the rear frame section with the frame rails from the '66. That way I won't have the big bump in the rear frame section. Then I'll weld the front Bronco floor section into the bottom of the '66 cab so it bolts back down to the frame in the front.

 

I didn't want to get into cutting the frame up. So I'm just going to raise the body to level it all out.

I'm making the transmission tunnel, firewall recess and front floors out of diamond plate steel. I'm using 16 gauge for firewall recess and trans tunnel. And 14 gauge for the floors and toe boards. And 10 gauge steel sheet for the firewall. Yes I tend to go over board on the materials.

Mine won't be a show truck. Just a cool daily driver work truck. I'm building it so when I get the cab all muddy I can just hose it out.


Here's my floor work so far.

 

Wow! That's nice work! Yeah, I usually use 18 gauge for everything. That's still thicker than factory. (maybe not a truck from the '50's, lol.) If I was repairing a case track bulldozer, I'd use that thick diamond plate!

Even in Minnesota, it'll take decades to rust that thing out.

 

Sometimes I can't decide if I'm building a truck or a tank!