Choosing a carb

[mattsmaverick]

I'm in the process of having a 250 I6 motor built for my 76 Maverick, and having a little trouble deciding which carb to go with.
The engine has been professionally rebuilt. Its bored .30 over, I bought a mild performance hydraulic cam kit from Classic inlines with a 264/274 profile,
and a 110 lobe center, it also has a pre emissions timing set. The head is off of a 1981 model 200, and has been modified for a 2v conversion, and has also been ported/polished to within
an inch of its life. The header is a 6 into 1 that I bought from Mustangs unlimited, but I may ultimately go with a 6 into 2. The engine will be bolted to a 4 speed toploader trans, and I'll be using a
stock 8 inch rearend with 3.00 gears that I pulled out of one of my parts cars
I originally planned on doing a very mild upgrade to the motor but things kinda got out of hand. My mechanic buddy tells me that the weber 32/36 carb I bought a while back wont
supply the air and fuel that this motor is gonna need. He's telling me I'd be better off with a holley 2300. What do you guys think? I plan on using this car just to tool around the back roads of North Florida. I don't plan on going racing, but I do like to put the hammer down once in a while.
Thanks.
Also if anyone could tell me how to post pics on this forum I'd appreciate it.

 

[ludwig]

There is a sticky about it but the short form is:

1) get a photo host like photobucket, snapfish or flicker

2) upload your photo

3) paste the IMG link including all the square brackets onto the message field of the F6F.

4) check if good with the 'preview' button

5) if too big: resize, try, resize, try until it is correct

6) click 'submit'.

You should be good to go. You cannot upload directly from your computer. BTW, the photo host site is where you can store and link your own avatar shot like the other guys.

 

[First Fox]

I vote Weber. I run a 32/36 on my daily driver and have another brand spanking new one from redline in the garage for when I add the freshened engine and the turbocharger in the fall. The small primary is awesome on mileage and flows plenty for my 200 when I need it. With this carb, an automatic and 2.73 gears I get 27 MPG on the highway. And I commute a LOT.

If the 32/36's 270 cfm of airflow doesn't seem like enough for you, there is always the Weber 38. It is a very similar carb to the 32/36, but the throttles are of the same size and work simultaneously. You still get all the tunability of the Weber design and I believe the 38 flows around 340ish? More than enough.

If you do some research on Weber carbs and can get over the "Gotta have a Holley to make power" thing, you will find them to be marvelous. Just be prepared to buy lots of jets and be prepared to learn to tune them. If that doesn't sound like fun, you might want to get the Holley or MC 2150. a little more "universal" out of the box, but not nearly as tunable.

 

[JackFish]

My vote would be an Autolite with 1.08 venturis, or the Holley 2300.
You may even be able to handle a 500cfm setup like wsa111.

 

[First Fox]

A quick run of an online CFM calculator shows that your engine will need about 282 CFM of airflow. This is assuming a 5200 RPM redline and a volumetric efficiency of 75 percent. The closer you stay to that rating the better the atomization will be, and the better it will perform overall. It is possible to destroy the low end torque of an engine to gain a horsepower or 2 with an oversize carburetor.

Weber 32/36 flows 270
Weber 38 flows 340 ish
Autolite 1.08 flows 287
Autolite 1.14 is 300
Autolite 1.21 is 351
Holley 2300 has either a 350 or 500 cfm rating.

The 500 is about twice the flow you would need and that is a bad thing. :nono: