Weber Carb

10/08/02 Today I attempted replacing the modified Holley 6250 with a Weber DMSA downdraft carb.
This Weber was supposedly originally installed on some sort of dual cam Fiat engine. It is slightly different from the "normal" Webers and Holley 5200s and is interesting because it has a manual choke and does not have a power valve.

After removing the stock carb I realized that my existing Mopar Performance rubber carb adaptor would not work.
Mopar Spacer
The Mopar spacer has a 32mm opening for the primary throttle bore while the Weber carb has a 34mm primary bore -the throttle plates would not open up all the way when the carb was bolted down.

10/11/02 I dug up an old stock aluminum carb adaptor and it seemed to accomodate the 34mm weber. However when everything was bolted down the primary throttle plate opened up but the secondary wouldn't because the mechanical linkage hit one of the bolts that holds the carb adaptor to the intake manifold.

The solution -raise up the carb.

10/14/02 I found two 1/4" carb spacers that came with some carb kits I got from eBay. These were originally designed for Ford applications and are approx 1/4" thick.
However -the stock carb adaptor studs are too short and will barely allow for one spacer. The spacers are also an open port design, while the stock carb adaptor has two holes to match the sizes of the throttle bores.

To alieviate this I modified one of my stock aluminum carb adaptors with longer studs, and bored the center section out, creating a large "open plenum" carb adaptor.
Modified Carb Adaptor
Whether or not this will affect performance is yet to be determined. I installed long enough studs so I should be able to install a third 1/4" spacer if I ever needed to.

10/16/02 Mounted the carb on the engine. The car runs and idles smooth at 900 RPM, I could not test drive it as the vacuum line for the new idle solenoid interferes with the automatic transmission kickdown cable... I will raise up the cable's mounting point which should allow room for the vacuum connection.
Kickdown Cable
I also have to find a more permanent mount for the manual choke cable which is currently running through the driver's side air vent.
Choke Cable

10/15/02 Took the car for a short test drive. The carb strangely seems to be running lean as it bogs a little under acelleration. It is currently using the same jets from my old Holley, I will swap in a larger primary jet and see what happens.

10/29/02 Modified the throttle cable bracket to make it .5" higher than before.
This allows the auto-trans kickdown cable and throttle return spring to be attached and should restore proper cable to carb geometry.
Bracket
The idle solenoid (the thing with the big vacuum line going to it in the picture above) does not seem to work on this carb. It does not seem to be necessary so I won't worry about it yet.

10/31/02 Changed the primary jet and the bog is gone. I have yet to test the car out on the highway though.. More to come...