quote:Originally posted by No Quarter:quote:If it is in sooner then the octane of todays pump gas can't handle it.
Does this apply here in Europe where we use 95 octane unleaded?
I can not speak for what is sold in Europe. I do know that I stopped using 100 octane unleaded racing gas. For my set up it runs like 93 octane.
It doesn't allow for any more advance before pinging then the pump gas does either.
I honestly don't know what the value is for it other then costing $8 per gallon.
My personal preferance on the distributor timing would be to set initial at 16 and limit total distributor to 20. Just setting initial to 16 I'll bet will bring your vacuum back to 18.
You need to experiment with the advance springs to find the optimum advance rate. The curve that they supplied you with is the stereo typical for a SB Chevy. If you have open chamber heads I think that is what you want but the closed chamber heads will ping like a champ.
Like Marlin said you don't want to reduce the total advance under 34. 36 would be perfect if you can achieve it.
I have found that yes you want to run the vacuum advance off of manifold vacuum, absolutely correct, but with a fast advance curve in the distributor, if you can run more then about 6 inches in the vaccuum can, I'd be very surprized.
The most common Ford factory vacuum cans are going to be about 14 inches. Don't worry though. They are adjustable with the allen wrench through the vacuum tube.