Model A down draft help!

I put a burns downdraft intake on my Model A with a single 94 carburator. Car is bone stock, and figured this would be a bit better carb than the leaky warped tillotson. Plus it looks neat. So i got it all set up and running this afternoon. Went to take it out for a drive and got to the end of my driveway before POP POP POP out the tailpipe like it had just run out of gas. Would not take any throttle at all. Stopped and let it rest at idle and it would take throttle again. Not another 800 feet and the same thing. Im thinking it might be that im using the stock gravity feed from the tank, but iv seen others run a similar setup and i imagine they dont have this problem.

Any imput? Im saving my pennys for a Stromberg 81

 

You need a fuel pump if you are going to use a downdraft carburetor.

Jon.

 

Top off your tank and see if improves your "range"

 

Moving the fuel inlet up 8 inches or so will affect fuel flow.
Think about it.

 

Fuel pump and a regulator.

 

The fuel inlet to the carburetor is significantly higher as mentioned above.

But another thing to consider is that even if the tank is still higher than the carburetor fuel inlet is the fuel inlet orifice size.

Carburetors originally designed for gravity feed have a much larger fuel inlet for the same size engine as those designed for a pressure pump.

A few examples:

1928 Chevrolet 4 cylinder (gravity feed) - 0.140 inch diameter
1929 Duesenberg (gravity feed) - 0.250 inch diameter (that is correct, a 1/4 inch hole!)

1955 Chevrolet 6 cylinder (fuel pump) - 0.081 inch diameter
1971 Pontiac 455 HO (fuel pump) - 0.135 inch diameter

Note the Pontiac 455 HO (fuel pump) has a smaller orifice than the 1928 Chevrolet 4 banger with gravity feed.

Jon.