Example please, why do you have to change it to a later dist. in a 54 when you put on a new carb. just like to no. Thanks

The OEM 'Loadomatic' vacuum-only advance mechanism distributor requires a very light vacuum signal (provided by carbs. designed to work in concert) to operate properly. The direct venturi or manifold vacuum tap on modern carbs. (?) would likely cause the distributor to be fully advanced at most all times, necessitating a very retarded initial timing to avoid engine damage, thus negating the concept of progressive ignition advance that is required for smooth performance. If you went to a 50's era 4 barrel carb (& manifold, assuming one is available that fits the 239), maybe you could successfully retain the orig. distributor and maximize performance by resetting the advance spring tension with a SUN machine.

6 VOLTS/POS. GRD. NW INDIANA

Early dizzy has vacuum only advance. it works with the old Holley carb. it will be very "doggy" with out the advance.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

I thank you now I get it

One other thing that needs to be mentioned if you still have the 239. You can't just drop a later distributer into your engine because the oil pump drive and the number of teeth on the cam/distributor drive are different than on the earlier distributor. Slot vs hex drive, 13 vs 14 teeth on distributor gear.

"The Master Cylinder"

Enjoying life at the beach in SOCAL

I've done the distributor switch on a 239 if you need help.

  Dennis in Lititz PA