Distributor Advance Springs

[drew43a]

can anyone tell me if the vacuum advance springs in the distributor are all the same or different for like a 318, 340 or 440 engine?

[73_Cuda_4_Me]

 Just to clarify, are you talking about the spring in the vacuum can mounted to the distributor, or the two 'mechanical advance' springs in the distributor?

[drew43a]

the 2 in the distributor connected to the weights.

[Chryco Psycho]

not exactly clear what you are asking , the factory mechanical springs are different , if they have been changed they could be the sme or different by changing only one spring or both with 2 of the same spring or 2 different springs depending what result was desired

[RUNCHARGER]

The springs were factory tailored to different engines. So the ones in a 318 with 8-1 compression and a mild cam were different than what the factory installed into a 10-1 compression 440 with a longer duration camshaft.
The factory service manuals generally had the specifications for the amount of distributor advance although not the RPM that it was all in at.