All,

I have a 406 small block with moderately high compression (10:1) and a crower cam, part # 00243, specs are all listed at the end of the email.

My problem is in setting timing. It seems my car likes alot of initial timing - around 19*. With this, my total advance is around 35* (vacuum not attached). I am still messing with how much and what kind of vacuum advance to run. I have an adjustable cannister, so I am leaning toward using a little, say <5*, manifold vacuum. My concern is seeing all the posts that recommend initial timing of roughly 12* advance, total of 34-38*. If I set my initial at 12*, my total, using my adjustable timing light, is around 25* WOT. I certainly don't want any pinging, but 25*? This seems a bit small. I realize that the 12* was for stock applications, so I'd like some advice from those wiser than myself -not terribly difficult- as to a rough idea of what my timing should be. Feel free to recommend anything.

Specs for cam are:

Grind Lobe Center: 284HDP 112*
Advertised Duration: Intake - 286*, Exhaust - 289*
Duration @ .050": Intake 225*, Exhaust - 230*
Gross Lift 1.5/1.5: Intake - .454", Exhaust - .463"

I have an Accel HEI ignition. Currently, I am running an Edelbrock Performer 600CFM carb -I know its too small, but I drive my car everyday, it helps on gas. I have an 350 Auto transmission, with a B&M Holeshot 2000 converter, thinking of upping to 2400.

I appreciate any advice you can give.

As always, thanks and God bless.

Mike

You may not be able to get the timing curve you are looking for with just the adjustable vacuum can. 19* initial seems like a lot to me. I like to run right around 12* initial and 34-36* total all in by 3500rpm. To me it sound like you need to tune you weights/springs to get the advance you are looking for. I do not run a vacuum advance any longer either. Though that is better for a daily driver (gas mileage and low speed performance). Have you played with the weights/springs at all? You may be money ahead to ither buy a performance distributor or have yours re-curved. Others with a similar combo may have a good starting point for you (ie.. what springs, weights, timing). Good luck that is just my $.02 worth.

I do have a recurve kit, but I was under the impression that changing the springs just changed how fast the mechanical advance comes in, not the actual amount of advance. If that is so -and I'm not sure that it is- I would still be only getting 15-20* of mechanical advance, 12* initial would put me at around 30 total, which seems low to me.

The only thing I can think of that might have to do with the springs is if they are so weak that I am getting some mechanical advance at idle, which would explain why my timing at idle needs to be so high to get the 34-36 total you are recommending.

Anybody?

You are correct that changing the springs and or weights just change the point of when the timing comes in and how fast. If you know nothing is sticking you may have to modify the slots to gain the extra advance you want. I know all HEI's are not created equal. Some are more performance oriented. I am not an HEI guru (I actually never cared much for them). There are guys on here that really know how they work and can probably tell you which ones are the better ones to have. Personally I would just buy an aftermarket distributor or have yours professionally curved (if you want to stick with HEI). Of course this is just my opinion.

I have a MSD dist. with an external
coil, but the springs and stops are the
same as the internal coil dist.
On my LS-6 I have the initial
set at 14 btdc and my stop will allow
it to go to 34 total timming.
It seems to run,start and shut down
fine. With an MSD dist. they send
two other sets of advance springs
along with the stock ones, also 4
seperate stops. This dist. is very
adjustable. I have one heavy silver
and one light silver spring installed
now and that gets all the timming
in at 3500 rpm.I had a holley dist.
before the MSD and in my opinion the
MSD is a much better product.