Re: 97 on a 49-53 engine- vac where?/doby/yoy mis
 

doby i give up cant be anything but a ford app. with that 3 bolt base and triangular shape. dont know why it wouldn't work. ken ct.

Re: 97 on a 49-53 engine- vac where?/doby/yoy mis
 

If you have one try it out and report back. I still maintain that if it doesn't have the same internal vacuum passages as a late 94 it won't provide the correct advance signal. If the vacuum comes from below the throttle plates it is essentially manifold vacuum which will not give the proper signal. The 94 has 2 openings, one just above the throttle plates and the other at the venturi. These are connected by a passage in the carb body. The signal provided to the distributor is an amalgam of the vacuum at the 2 different openings, more from one or the other depending on throttle position versus engine load. Pure manifold vacuum would provide too strong a signal, ie: too much advance under normal road load or part-throttle operation. Under acceleration manifold vacuum drops off which would allow the retard springs in the distributor to retard the spark too much. When you think about it this system is rather ingenious and when in proper working order probably worked pretty well for a box stock engine.

Re: 97 on a 49-53 engine- vac where?/doby/yoy mis
 

Doby, I think you have it right. The later 97 seems somewhat of a compromise. They have the same vacuum source just above the closed throttle plate as a 8BA 94 but at least the one I have, is not connected to a venturi source. The base does have a extra hole for connection to the center bowl so maybe a special bowl with the proper venturi source has been changed out on the example I have. It probably performs better than a standard 97, but not as good as a 8BA 94.

Re: 97 on a 49-53 engine- vac where?/doby/yoy mis
 

you guys may be right i dont see any extra hole in the middle section either,maby its not the correct middle section for the vacume base. parts could have been mixed up yrs. ago. will keep looking for a middle with an extra hole in it. ken ct.