Ok, thats a good start..............

So what you really have is a 1962 galaxie carburetor off of a 352 so thats great, this carb should work perfect with your 1963 352 car.

So lets figure whats up. So you were saying it was hard to start and you found some missing part(s), also when it was running the idle mixture screws had only slight to moderate effect.

SO (other than the missing parts) sounds to me like you didn't get some parts and passages clean enough, that could be part of the hard to start and definetley the cause of moderate idle mixture screw effect.

My recomendation is to take the carburetor off, spend lots of time getting all those passages clean especially the venturi clusters, use a good carburetor cleaner to soak them for more than overnight and then use some wleding tip cleaners to make sure all the passages within them are clear and clean, same with that carburetor body. Use compressed air to clear them out.

When you have it apart, take time to make sure you are not missing anything, and you have it all back together the way it is suppose to be. If challenged go borrow a 62 shop manula from the library or copy the carburetor section.

Those float levels should be set at 21/32 for both primary and secondary. That measurement should be best taken with the carburetor UPSIDE DOWN (to avoid putting pressure on the sensitive needle valve) and measured from the flat of the top of the main body to a point on the float 1/8 from the end AND NOT ON THE SEAM but on either side of it. Best way to do this for begginners is to measure 1/8 from the end of the float and put a pencil line there, then when install you have an exact parallel to place the enclosed tools that came with your kit.

Remember since you have a 1962 galaxie carburetor to use THOSE bench specs when bench setting the carb. (all 62 4 barrells where the same whether for fullsize, merc and/or t-bird.

Hope that helps,

Bill White
White Automotive