The 22 gallon tank on my '78 G10 is badly dented, rusty and jiggles around when I go over bumps. I hate it.

Replacement tanks are readily available from Spectra in both 22 gallon and 33 gallon, so I'm thinking it would be cool to go with the bigger tank.

The 22 gallon measures 31" long x 22" wide x 12-3/8" tall, and the 33 gallon measures 31" long x 31" wide x 12-1/4" tall, so the only significant difference is the width.

Has anyone made the switch? Will it be as easy as removing the old tank and using the correct straps to install the new one?

I haven't done it yet, but want to. I've replaced quite a few fuel tanks over the years though, and they are usually pretty easy jobs. I've been looking all over for a 33gal for my 82 and haven't found one, so I'm glad you mentioned Spectra. I bookmarked that one quick.

Should just be as simple as drain, drop, install with the new straps. Might want to get a hand pump to drain them. I've used a kerosene bulb style pump and a hand pump that looks like a bicycle tire pump. Both worked fine, but the kerosene pump took a LOT longer.

Oh and don't do it on asphalt, gas will eat holes in the asphalt. Don't ask me how I know that one. DOH!

Right on. A buddy of mine who runs a garage with a lift will be helping with the work so removal and installation shouldn't be a big deal. I just wasn't sure if the bigger tank would bolt right up.

I figure they wouldn't make both sizes if that wasn't the case, but you never know...

Yeah, I haven't done that specific swap, but it would make sense that everything should fit in fine with the only minor modification being you might be missing a bolt hole or two for the new straps in the chassis rails or something. Something I didn't think about was the sending unit. But the measurements for depth look the same, just wider, so you should be fine with the existing sender. Keep us posted on how it goes, I'm super anxious to order one myself now, but I should probably get the darn thing running first.

Spectra makes and sells one sending unit that can be used on both size tanks, so hopefully it will be a smooth swap.

Is it a long van or short van? You can't put a33gallon on a short van no way

My '93 has the 33 gallon tank...not sure if the underside is the same 78 vs 93 though. I'd take pics but alas my van is in the shop...AGAIN for a drivetrain vibration issue nobody can seem to fix.

Why? The only thing different about the bigger tank is the width. The length is exactly the same.

Won't fit between axle and back of van.
Axle is too close too back of van. I know people who tried it.

Sorry guys. BTTT. Lionhead is right on the shortys.
Even on the standard wheelbase models the cross members that the tanks snug up into are different. The 33 will not fit without cutting out and moving the cross member. Not an easy job on a unibody chassis.

Well then...looks like I'll be buying a new 22 gallon tank! 😂

CRAP!

This is probably what the other thread I resurrected from the dead (thanks google) was on about. Apparently they did it. …but does this mean on my LWB I'm good to go w/a new strap kit?

33 gallon tank on closeout special at rockauto at the mo.

Nice, $120 for the Spectra on closeout, but the Liland and Dorman brands are $130 & $150 normal price, so that's not too bad either.