I just got my advance curve kit . I've got a bunch of springs and I can limit the weights EXACTLY where I want them now.

I'm going to try 16* initial with 16* mechanical.

Right now I'm running 16* initial, 12* mechanical (I was limiting it blindly, now I can limit it exactly with the kit) and 12* of vacuum advance and getting 11MPG all city driving.

I have instructions that came with the springs. According to the advance curve graphs I was given, the stock springs don't start adding mech. advance until 1100RPM. @1500RPM it's giving 7*, and at 2000RPM it's giving 14*.

Now, since I"m going to limit the weights so that the maximum I can get is 16* mechanical I want to push the curve back. I have 12 spring curve combinations to choose from, and graphs that tell at what RPM how much advance is coming. What kind of curve do I want? Do I want around 5* @ 1500RPM and 16* @ 2500RPM?

There is no combination that will deliver 16* @ 3000RPM, I'm limiting it so much. (considering it comes from the factory to deliver 24*) The latest I can get 16* to come is around 2500RPM

Setting the car up on ported like you suggested definately helped gas milage. Should I keep 16* initial?

Thanks again :hail:,
Dave

If the best you can get with what you have is full advanc at 2500rpm (16degrees) then go with it.

You'll have to experiment with exactly how much total advance the motor needs to make maximum power.
It will be 32 to 36 total.

You could keep the 16 initial, increase the travel to allow
18 deg advance travel (which will occur a little later with the same springs) 16+18=34
Or if the motor needs 36 degrees total... advance two degrees for 18+18=36
Then fine tune in the vacuum advance.
As long as it does not detonate either at WOT or while rolling into the throttle from cruise speed or surge while cruising or show blueing on the plug tips etc you should be ok.
The car is never going to be super great on gas around town because of the cam but should be much better after tuning and fairly decent on the Hiway.

Did you try the Sunoco gas?

I've been running the Ultra 94 for a couple weeks now. I wasn't pinging/detonating before I switched, but its been running fine on the 94. The Ultra 94 is like .02$ cheaper then Mobil 93 so it doesn't bother me.

The best curve I've found is going to give 16* @ 2400RPM.

Now the kit instructions says that by slightly bending my spring perches, I can delay the entire curve by as 300RPM.

Assuming I bend the perches, the curve I'm going to use acts like this (purple/orange springs):

MA=(mechanical advance)

1000RPM: MA starts to come in
1250RPM: 5*MA
1500RPM: 10*MA
1750RPM: 12* MA
2000RPM: 13* MA
2250RPM: 14* MA
2500RPM: 15* MA
2750RPM: 17* MA
3000RPM: 21* MA

As you can see, I'm going to top out around 2700RPM assuming I can bend the perches correctly to delay the curve an extra 300RPM. That spring combination has a steep curve from 1000-1500RPM, then it really slows down between 1500-2500RPM (which is what I need), then it starts to really pick up again once it gets to 2500RPM. I'd scan the graphs in, but I don't have access to a scanner right now.

I wish I understood timing better, how piston speed and flame speed affects advance requirements over the entire RPM range so I could fine tune my mechanical advance better. Since when I'm cruising around town or when accelerating occurs between 1000-2000RPM generally, it would be nice if I understood timing enough so I coulld manipulate my 1000-2000RPM mechanical advance to optimize efficiency.

Thanks for the input, if your ever in NJ I owe you quite a few beers.

I just noticed that, so when fine tuning WOT timing, I should change mechanical, not change initial? I guess theres no way to determine exactly how much initial is most efficient for me. It looks like I'm going to get REALLY good at installing distributors.