28* initial timing for a 318? How can that be?

KevinCar said
Thanks Mattax
I have an isolator its thickness is 0.320, edelbrock 9266. I also bought some insulating and reflective sleeve for my fuel line from pump. i am also looking into some coated Dougs headers to replace the old low hanging hedmans that radiate super heat. Just havnt installed until i sort out wiring and timing, first.
i will map my curve as it is current and perhaps go from there by hiring a recurve by shop with dist machine.
i was looking at an FBO plate and spring kit, then their ecu, and curving myself via mapping, as they report the oem black box ecu i have (plus ole school oem spare) will retard timing over 3500k.
But do i really care?, its not a drag car and already doesnt get traction under hard acceleration.
your advice on using the idle air to control idle speed somewhat along with idle screw, timing and maintaining t slot makes sense vs just timing and idle speed screw, combo to best power/vacuum at idle.
I really just want efficiency via use of vacuum advance without detonation or long term damage to my engine.
So after initial and curve and full mech advance, i will have to sort the vac canister out for my motors vacuum.
Again a bit confusing as some people state manifold vac and others ported vac. i really need to look at just how quickly ported starts and ends in rpm to see where it is pulling more timing, but manifold vac may raise timing enough to keep motor cooler, especially at idle or slow in traffic, which is an issue also when hot out. might "wake" it up quicker under acceleration if it has more vacuum timing in the curve also.
Appreciate your helpful information.

If the distributor was setup for the cleaner air package (CAP) then it was meant to be used with a retarded initial timing.1 In those situations, sometimes a manifold source is a quick and easy way to get initial back up where it would have been pre-emissions controls. I've posted graphs showing that - you've probably seen them.2

FBO kit: Although he has changed his kit and recommendations over time, he's still only partially correct. It's impossible to have a discussion with him. He's come on here several times with his diatribe and then disappears when a real discussion starts. His plate design is the reason a factory ECU seems to retard. Its also the reason for many years he said it couldn't be used with vacuum advance.3

1. See the Master Technicians Service Conference. Hard to beat the factory info when looking for good information. If you can recall pre-internet how difficult it was to find technical service bulletins and factory tech info, its easy to understand why a lot of speculation and assumptions were made by hobbyists. See for example 1967 Combustion in Today's Engines and Introduction to the CAP Story. Timing is also discussed in 1959 Introduction to the new distributor, and 1970 Lets Keep it Clean.
Available at the Online Imperial Club linked above, and mymopar.com
2. 1967 Service Manuals have timing specs for both CAP and non CAP versions of most engines offered that year. Graphs comparing the 440 Hi-Po timing
3. Videos showing what happens to timing with an electronic box when the distributor's advance is stopped early Lets Revisit Timing