Re: 51Packards....52 Packard 200 Deluxe!

Posted by HH56 On 2015/1/4 17:23:19

Earlier manifolds had a large vacuum port in the middle under carb as you have indicated and smaller ones at each end of the intake runners --front one was used for wipers & was on top almost directly above the fuel pump. Rear one was usually plugged but could be used for a vacuum antenna or other option if desired.

Later manifolds starting in 51 or 52 eliminated the end ports and just used the large one in the middle for wipers. If equipped, they added a tee fitting to supply the power brakes also.

If your fuel pump is one with rubber hoses connecting metal tubes to the vacuum pump section you can attach the vacuum gauge to the line coming from that port. If yours is the solid metal connection then you will have to get some kind of adapter fittings to plumb the gauge into the port but in either case that is the correct place on the manifold to measure.

Some carbs have a removable plug on the base as a spare port that could be another vacuum source. If using that you have to make sure it is the one connected to manifold vacuum from below the throttle plate and not the port used for vacuum advance.