Carb / intake options without modifying doghouse

Hey folks, I've been lurking on this site for awhile but never posted anything. Gained a ton of knowledge from you guys already !

Bought a 66 Supervan with a pop top about a month ago and am loving it !

Basically to get this thing back on the road I had to rebuild the old Autolite carb and replace the vacuum advance diaphragm, minor points adjustment, etc...

The engine seems to run great but seriously lacks top end power, and I'm only getting 10mpg.
I'm not seeing or smelling any fuel leaks and I'm kinda stumped as far as the gas mileage goes.
As far as top end power, it seems like that may be as good as it gets with that little carb.

Ok, so here's where I'm at ...  Is there any intake out there that will fit in my doghouse with out cutting into it ? After searching like crazy I'm coming up with nothing .

So my other option was to buy the single to double barrel carb adapter and install a weber (which I already have ) I realize I'd be shoving more fuel through the same small hole, but is this my best option ? Did anyone manufacture a 2 barrel manifold ?
Again, I don't want to modify my doghouse.  Any insight would be much appreciated.
thanks

If it's a good solid truck, and you're gonna keep it, put in a nice 302. Lots of on-line info about the
experience. You will be a happier camper. And with stock exhaust manifolds, you don't need to
modify the doghouse on the '66.

Going to assume you have a 240ci engine?

Yep, Its a 240ci with the later style c4 trans

Something's wrong if you're only getting 10 mpg. Might double check your timing. Carter YF or the later YFA carbs are a nice bolt on upgrade and let you change to a Duraspark ignition and distributor. Look for one from a 300 ci. That's what I'm running.

I've been considering that, going with the duraspark is definitely on my list of priorities, but is the carter yf really an upgrade ?
As far as my mileage, timing has been checked many times, my advance is working great , I've had my base timing anywhere between 6'btc - 14'btc and haven't seen a difference in mileage. I'm pretty sure there must be a fuel leak somewhere, maybe my metering jet isn't holding pressure or leaking while the engine is shut off.. But I haven't smelled fuel and I don't have any starting or running issues like as if it was flooding or fouling plugs.

Really what I'm looking for here is .... Does anyone know if any company or manufacturers made a 2 or four barrel intake manifold that will fit in the doghouse , or am I stuck with the stock 1 barrel manifold and cheesy 2 barrel adapter to put a Weber on .

I've looked and nothing fits.

What about cutting up and welding the a clifford or offy JD?

https://vintage-vans.forumotion.com/t50283-25-intake-manifold?highlight=manifold

Home made option.
https://vintage-vans.forumotion.com/t52302-dual-carb-or-2v-building-intake-for-custom-carbs?highlight=240+intake

I sold the Clifford on ebay cause it didn't fit and I couldn't cut it up. I ended up building a manny as an experiment and it worked okay but I took it off to have the flange machined flat, since I couldn't get it to seal properly. I tried out a Autolite 2100 and it fit okay with no mods to the doghouse. I may do a redesign cause this one was pretty basic.

The fuel line at the back of the carb cleared the side by half an inch. I ground off just a tiny bit of the accel pump arm to get extra space, although it prolly wasn't needed. This is in a 240 doghouse.

That looks like a pretty good fit, and you got rid of having the exhaust bolting to it

Yup. I made a plate to close off the top of the exhaust. A 10 wide by 2 inch tall air filter fit fine under the doghouse lid. I bent up a piece of brake line and clamped it to the exhaust to create a hot air choke.

Thanks everyone for all the great replies, I'm loving the idea of building my own intake or shortening an offy manifold. For the time being I'm going to install a weber 32/36 with a 6cylinder jet kit, along with a little porting of the manifold and adapter. Also will be swapping over to duraspark 2.

I'll make sure to post about how it all goes along with jetting and what not. thanks again

Well, this last week I converted my van to the Duraspark 2 setup and pulled the old Autolite 1100 carb off. It turns out that the Weber carb with 2 to 1 barrel adapter doesn't fit in the dog house either.
So for now I'm running a Carter YF carb and there is definitely an improvement from my previous setup.
Still lacking top end power, but I just completed a 400 mile trip through national forest land and got 14mpg on one tank of gas going a steady 70 mph , and got 17mpg just cruising around 40mph through the forest.