Vacuum Advance and why to use it on the street

[Keith Tedford]

The original factory advance setup in 1969 wasn't even for performance. It was to pass emissions tests. Our 427 came with #68 primary jets and had lean surge at sixty mph. The advance curve was long and slow, not coming in full until about 5K rpm. I forget the exact number any more but I bumped up the initial timing and played with various springs and weights. The difference in performance was impressive. That was when we could get 104 octane gas. With the 91 octane today you can't run nearly as much total advance. I had our L78 running reasonably well but it sure wasn't running original factory specs in the distributor. It will run but not all that well.

[Hemicolt]

There is so much that is being left out here.
Compression ratio and camshaft specs. play a huge part in how much pressure and heat are in a cylinder. Anyone who has looked into camshaft design knows timing events and overlap in a cylinder cycle will determine pressure bleed off.
My engine has thousands and thousands of miles on it. No melted plugs, ever.
Every year I pull the rocker arms to check wear. While doing this I always do a leak down test and have never found any problem in the ring and cylinder package. Engine has no blow by and uses no oil.
This year as well as every year in the past, since the car has been built, I will drive this car in heavy traffic and enjoy not having to pull over due to over heating.
To say that every motor needs a V.A. and can not run a locked out dist., due to todays fuels, shows you may need to play catch up. Contact Patrick James at Pro Systems, if you would like to check my information.