Duraspark spring rates

Jim Dandy · #1 (**permalink**) 03-03-2002, 04:44 PM

Anyone know the stock spring rates for a Ford Duraspark dist. ? Also what rpm full advance is reached. Thanks !!! .... Jim

Jack21 · #2 (**permalink**) 03-03-2002, 07:15 PM

Jim, I have a '76 Motors Manual with distributor spec's in it based on the specific part # of the distributor. It's not listed by engine size.

Generally speaking, the stock setup has the advance starting at 1000 RPM (crank), and maxing out between 10 deg and 14 deg at 4000 RPM (crank). Vacuum advance varies from 10 deg to 25 deg (crank). These are '73 - '74 specs.

Spring rates are not listed but with advance curves like this, you're not likely to be using them anyway. Get a curve kit with weights and springs and the instruction sheet will give you the approximate advance curve for the spring combinations. Better still if you can find a shop with a distributor machine to dial it in for you. This seems to be a lost art today.

While you're at it, get an adjustable vacuum advance for it also. As you bring your centrifugal in earlier, you'll need less vacuum.

My 351 has 20 deg centrifugal, all in by 2500 RPM. Initial lead is 14 deg for 34 deg total. Vacuum is only 8 deg for cruise.

Jim Dandy · #3 (**permalink**) 03-04-2002, 05:23 PM

Thanks Jack !