If I remember correctly former user StephanieBrite77's 77 Volare 2 door super six and power brakes and steering was able to achieve 21-24 mpg highway once everything was tuned up and dialed in (she even cut a perfect light at Woodburn in that thing too...LOL).

Not bad for a $700 junkyard find...

-D.Idiot

One of the main differences between the 318 and 225 BBDs is the orientation of the choke thermostat eyelet on the side of the choke butterfly valve. The 318 BBD has this eyelet oriented to be pulled straight up and down, while the 225 BBD has the eyelet oriented to move in a diagonal fore and aft motion. Using a 318 BBD on a slant six without address the difference in the choke linkage will lead to a choke that does not operate properly, and usually stays partially closed. A partially closed choke will lead to poor MPGs and leaving black soot on the driveway. User Fab64 came up with a very simple and elegant solution to using a 318 carb on a slant six. Do a search for fab64 and choke linkage to find threads with the pictures and description.

20 MPG is achievable, but you really have to get the motor and carb tuned well to do it (and drive to maximize MPG).

The description of the differences between 225 and 318 carbs start at page 26 in this manual, available in the FAQ in the forum's Engine section.
http://www.slantsix.org/forum/viewtopic.php?t=33102

You'll also find info on electric chokes lower on that page.

Here are parts lists so you can see different combos of parts for trucks and cars: http://www.slantsix.org/forum/viewtopic.php?t=43724

The differences between 225 and 318 BBDs, refer to cars with EGR and possibly other environmetal equipment. If your truck had neither, you may be able to fine-tune a 318 carb to suit your engine, even if the smaller venturies in the 225 carb is better for low and medium speed responsiveness. Throttle plate size is the same for all, the top part of the BBD also has a different choke plate.

Olaf.

The choke thermostat for cars is the same as the one for trucks and vans. However, both of the links you provided have problems.

The eBay link will work for a slant six, but it is missing the wire for the electric choke assist. On all factory Super Six installations the choke thermostat used both heat from the exhaust manifold as well as an electric current to open the choke. The eBay thermostat has had the wire for the electric choke assist removed. This will make the choke stay closed too long resulting in in poor economy and performance.

The O'Reilly link is for a v-8 application where the choke thermostat sits directly below the carburetor instead of behind the carb like the slant six.

Your best option for a new choke thermostat is to purchase one of the Carbs Only electric choke retrofit kits. These kits are a significant improvement over the old original design choke thermostats. The Carbs Only thermostats actually work and are infinitely adjustable. See HERE. You want kit 1232.

Have you read the Super Six conversion article? If not, you should. It is hosted right here on this very website, right HERE.

Here are the pictures of the choke anc linkage, they are high res so I'll just link them. I ordered the electric Choke from NAPA, the closest one was in New Jersey! Be warned if wanting one from NAPA, you'll have to wait for it to ship.


Choke Linkage
Choke shown more clearly here.

Is there anything I can do for the time being to drive the car with out it eating gas? Can I remove the electric heat assist choke for a few days while making sure the car warms up in the morning?

You have the correct 225 BBD choke thermostat that appears to be undamaged but you are using a 318 BBD. In the pictures you posted if you had a slant six BBD and the choke eyelet was in the position shown in the pictures, the choke flap would be fully open. Since you are running a 318 BBD when the 225 choke thermostat is in the "full open" position the choke plate on the carb is still 1/3-1/4 shut. This will lead to very poor fuel economy and performance.

Can you describe, exactly, or better yet post a picture, of what you are referring to as the "throttle body"? Are you talking about the bottom casting of the carb that houses the throttle blades?