Need help/advice on setting timing with mechanical advance

[85_SS_302_Coupe]

I've been talking to a guy about timing and it's got me thinking about if there's a better way to set mine up. I've always just set base timing and left it at that. Well, now i've got a mechanical advance distributor and he's telling me i should set it for total timing and not base timing. So, my questions are:

1) does anyone know which kit i need to adjust the mechanical advance curve? I've been on Summit but there's a bunch of them...i've got a Mallory Comp 9000.

2) which is better and why, setting for base timing or total timing? What happens if i set for total timing and that makes my base timing like 18* or something?

3) If i set it for total timing, what's a good place to start?

[PHAT69AMX]

Hope you have a Dial-Back Timing Light, that's what's needed.
Understanding is somewhere between 36-40 degrees total advance is what's wanted
and all in by somewhere between 2000 and 3000 rpms, as soon as possible without getting detonation. The Mechanical Advance in the Dizzy has a Travel Stop mechanism that determines how many degrees of Mech Adv it can allow. The Initial timing will be added to that to get the total, so if there's 24 degees mech adv in the dizzy, then initial will be 12 degrees for 36 degrees total. The weight's and springs determine when the mech adv starts and at what rpm it all comes in. All of this does NOT include any Vacuum Advance, which gets added on top of the 36-40 total Initial and Mechanical. Most dizzy's are set up conservatively and do not give full mech adv until like 4000 or higher rpm's. All the given figures are Crank Degrees, gotta be careful because when talking about dizzy's because they turn at 1/2 the rpm of the crank and any angles given in dizzy degrees must be doubled to get how many degrees will be seen on the dampener at the crank when read with a timing light.

What distributor are you using ? Oh, I see you said a Mallory Comp 9000.
They offer more than one Mech Adv curve kit for it ? Wonder why ?
Haven't messed with one of those, have done MSD dizzy's.
They have changeable mech adv stop bushing to set the amount of mech adv
and a selection of springs to set start point and full advance point.
And springs of 2 different tensions can be mixed.
Best way to set one up is with a Disributor Machine but have been unable
to find a shop who has one of those anymore.

[PHAT69AMX]

Always found Mallory Dizzy Series Numbers and Model Numbers confusing.
It looks like you need Mallory YL Advance Curve Change Kit #29015
but not completely sure if it goes with the Comp 9000 dizzy or not
but it is the only advance curve kit Mallory offers that I could find on their page.
From the instructions it looks like the amount of total Mech Adv is adjustable
and originally factory set for 24 crank degrees total mechanical advance.
But depends on what Series and Model the Dizzy you have is.
Is there more detailed Series # and Model # info on a tag on the Dizzy ?

#29015 Kit is $38 from Jegs.

link to the Instructions for the #29015 Advance Curve Kit

http://www.malloryperformance.com/pdf/29015.pdf

[85_SS_302_Coupe]

The part number is 9170401A and it says Comp 9000 Unilite Breakerless Ignition on the tag. Thanks for the help.

[PHAT69AMX]

Glad to help. Took another look at the Mallory site and they do offer another Advance Curve Kit
for YH & YT Series Distributors under #29014 which I think is the one used for
the Comp 9000 Distributors rather than the #29015 kit mentioned before that is for YL Series.
The #29014 kit is $32 from Jegs.

link to Kit #29014 Instructions has pics, do they look like your dizzy's internals ?

http://www.malloryperformance.com/pdf/29014.pdf