I just got a new Pertronix upgrade kit for the HEI distributor in my '78 L82. While it's an easy install, it comes with three sets of springs with the new centrifugal advance weights. To pick an rpm figure of 3000 rpm's, the springs are made for advances of 23 degrees, 19 degrees and 15 degrees.

I don't know which is the best set of springs to pick. I'm not after max power, simply improved response and driveability. My engine has a bigger cam installed by a previous owner (specs unknown to me), and an Edelbrock Performer intake with the original Q-Jet rebuilt and re-jetted to match the cam.

Pertronix doesn't as yet have a help line. Any advice from members here as to which set of springs best suits my needs will be greatly appreciated. Thanks in advance.

For maximum power you want 30-32 degrees total advance at 3000 rpm. with your 23 degree springs you can achieve this with an initial advance setting of 7-9 degrees. If you don't care about making maximum power, go with the 19 degree springs, or go with the 23 springs and just keep your foot out of it. The main thing you have to watch out for is "ping" if you start to detect this you need to back off on the advance until it goes away. Helps to run only premium fuel, if you don't want to run premium, definately do not use the 23 degree springs, and even the 19's could be too much.

|UPDATED|3/23/2004 3:49:50 PM (AZT)|/UPDATED|

Agreeded. You may also find the lesser advance springs may allow a bit more timing a idle. The problem here is you may have too much timing at heavy throttle. I know it seems weird but remember, timing advances as throttle and speed increase, then retards at Wide Open Throttle (WOT). The mechanical advance works with rpm alone. Vacuum advance increases as the throttle is opened, but retards back to mechanical advance alone at WOT. This is due to the lack of vacuum with the throttle wide open. It's also a good thing, or the car would ping at WOT due to richer fuel mixture. Above 3500 rpm it won't make and difference, except the varation at base timing settings. Depending on your set up it may take a bit of trial and error. Follow the advice from Big Fish, then experiment a bit.

Ken Styer

|UPDATED|3/24/2004 10:44:52 AM (AZT)|/UPDATED|