About a month ago I picked up a very solid C7 distributor out of an 360 engine while parts hunting. Intended to take it apart and rebuild. Yet shaft and bushings were soild so there was no need to go there and it sat for a few weeks. Started reading about ignition and timing curves on the web and decided to experiment some.
Took that good distributor apart and cleaned everything on the inside. Saw that the mechanical advance was set for 20 degrees which combined with your basic 6 degrees BTDC, as per Ford, would give you 26 degrees total advance. Plus there is a mild spring inside and a heavy spring inside which probably gets you your full advance in by 4000 rpm. So I reversed the stop 180 degrees to the 15L postion which equals 30 degrees mechanical advance. Also removed the heavy spring and put in a light one from my Mr. Gasket set that was laying around.
Now I pulled the current distributor out of my 360 and saw it should be out. The O ring was shot and the end play was a whole 1/8 of an inch. It was drilled twice so someone did something to this dizzy long ago and couldn't set the end play correctly. So the messy one is out and the brand new looking one goes in. Set everything up with a new brass contact Motorcraft cap and rotor to go with the pertronix already on. Also took the chance to take off the mid 70's valve covers and put on mid 60's FE covers that were picked up and restored.
Started up the engine after setting the choke. I have a manual Autolite 2100 rebuilt by Pony Carb on the truck. Got her up to operating temp and then went to set the initial advance with my timing light and vacuum gauge. The truck really liked 12 degrees initial which gave a smooth 19mm Hg and smooth idle for the first time. Initial of 10 degrees gave me 18.25mm Hg and still a good idle. She doesn't like to be any lower than that. Makes sense since FE combustion chambers in the heads are not very efficent at helping the spark burn the gas. Checked total advance, with the vacuum line disconnected and got 40 degrees as one would expect and in by 3000 rpm. Hooked the line back up to the big cannister type vacuum unit seen in the 70's.
Took the truck out and the first thing noticed was how much smoother the truck was when stopped at a light. That was great right there. Next there was no longer any hesitation when taking off from a light. No more feathering the gas pedal. There is a freeway entrance that requires a left turn and then you head up the grade to the freeway. The truck always lumbered up this entrance. Not today! She shot right up that entrance like a bat out of hell with not one complaint. Who ever said the 360-2V was a dog now knows why. Without a doubt the truck has acceleration I wouldn't have believed and it was very smooth and steady. Went back and forth on the freeway racing past everything and had no pinging. I will definitely need disc brakes now as this is not your fathers truck. Will have to see how the gas mileage works out but it won't be lower that I know.
Further experiments would be to find some 13L weights to swap in for 26 degrees combined with 12 degrees initial. Maybe put 2 light springs in. For sure a correct looking 60's vacuum advance unit that will now be adjustable is on order from Gyrhead. This will enable me to adjust my vacuum advance based on how the engine operates on a moderate load with the newer settings it has. I can dial in 10, 12 or 14 and check things out and then dial back if I hear any pinging. Vacuum advance is in play when driving part throttle on the freeway and having 50 degrees in use is not unusual. To get your best gas mileage that is where you would want to be. Of course, the other 3 cars are all going to get similiar work but according to their particular engines since there is a modified high compression 302, a standard compression 289-2V and a high compression with tall rear gear 410-4V each having their own unique needs.
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