This write up applies to 1956 stock intake and motor. After my last incident with vapor lock and a leaking Rochester stock carb, I had two options: rebuilt it and hope for the best or replace it. My car is not 100% stock. For the most part it is but it not a 100 points car. My main concern is drivability and peace of mind, so this might not apply to you. Don't condemn me or criticize this conversion as it is used as information only.
New Edelbrock 1406 600cfm electrick choke carburetor from Jegs
TD trans dapt 2064 from Jegs (kit comes with studs)
Stock fuel line and vacuum lines were removed. Unhooked the throttle arm and return spring, then it was a matter of removing the 4 nuts from the carb studs. Carb came out easy. The TD adapter is the closest match I could find. Spent hours on the phone with parts people and this was going to work but it needed a slight mod. Once the adapter stud holes were drilled (they come pre marked but not pre drilled) it sat on the stock intake but the stock intake studs were protruding and the new carb would not "sit" flush with the adapter. The adapter was counter-sunk and one inch long 5/8 counter-sunk screws were used after the 56 year old stock studs were heated and removed.
The hot air pre-heat holes (air from the right manifold is used as carb heat during cold starts, but it also heats up the stock carburetor after it is warm and as a result it contributes to vapor lock.) I drilled and tapped the pre heat holes for 5/16 brass plugs. I came to that decision after I saw that the adapter was leaving a gap between the intake and the adapter itself. Even with the gasket air would leak. So opted to plug them. Then the intake was washed in the parts washer, set the adapter on the intake, screw in the 4 counter sink screws using red loctite. The adapter is tappered and the narrow holes go down towards the intake, the larger holes up towards the carburetor base.
Insert the carb hold down bolts from underneath the adapter before you screw the adapter on the intake. Once the adapter is on the intake simply put on the carburetor supplied gasket and bolt the carb on the adapter. I used new manifold gaskets and this is where I am as I had to go to work. But the Edelbrock is on and from what I was told by Jegs it can handle up to 6 to 8 psi at the inlet, which is what my electric pump maxes out. I will get it running over the weekend and will post an update then.