After listening to lots of good advice on this forum, I'm looking into changing the distributor on my '54 Merc to something with centrifugal and vacuum advance. If I retain the Holley 4000 carb, where do I get the vacuum to drive the vacuum advance. I'm assuming that the existing vacuum port on the carb with the spark control valve will not allow the proper signal. I'm thinking of a '58-'64 Y block dist., or a modified 289-302 type, but as I recall they didn't use full manifold vacuum???.  Thanks : Bruce

There has been an ongoing debate on this forum between those who use direct(non ported) vacuum source and those who use the ported(carb controlled) source.If you do a search of topics(use "distributor vacuum source" as your topic)) using the search feature at the top of the page you can get some ideas of the pros and cons.I personally use direct vacuum.If you change distributors( I did) you will still need to do some setup as far as total available advance and limiting the vacuum advance to about 8 degrees available.Once you do this swap you will never regret the extra work and expense involved.Really wakes up even a stock motor like mine.

  

Thanks oldcarmark: Looks like I don't have a choice anyway if I keep the Holley 4000, but will be able to upgrade the carb at a later date much easier once the distributor issue is resolved. Bruce