[A Snake]

I would go with Tim's suggestion of using the hose or tube between the vent tubes. I would also add that unless you have a lot of cam and at least 11:1 compression, a 750...especially a double pumber, is a lot of carb for a 351.

Here are a couple of thoughts for you:

1. If cost is not a huge issue, call up the Carb Shop, give them all of your specs. They will want to know all about the engine, the weight of the car, gearing etc. They will then recommend and provide a carb that will work. They built the one on my 427 Side Oiler and it has never given any trouble of any kind. It also has "four corner idle" which you might like for yours. If you have a dual plane manifold, it allows idle fuel to be metered through all four venturis....especially helpful with a bumpy cam.

2. Money or not, it may be that simply buying a 650 propared by Holley will solve the problem. I'm absolutely certain you'll find the engine a lot crisper with quicker throttle response. Ask yourself which do you want most; a car that runs like a raped ape at wide open throttle on the drag strip or one that you can drive on the street and push in the corners on a race track. On a good day, a fairly streetable engine like yours will get about 65-70% VE (volumetric efficiency) You can take that percentage against your intended RPM curve/displacement and it will tell you how much air your engine will flow. Remember....it's just a big pump and opening a bigger hole won't make it pump any more. That is all determined by cylinder head/manifold design, piston dome shape compression ratio and camshaft geometry.

HP Books used to print a great book on Holley carbs and gave a lot of information on airflow.

Hope these thoughts help out.

Al