MSD distributor-Best springs and advance bushing

The best total timing for most Buick engines is 30-34* at WOT. The engine will really respond well with that timing in by 2500 -3000 RPM. When you do bring the mechanical advance in that early, it is advisable to limit the amount of vacuum advance degrees to 8-12* maximum. If your MSD distributor is one with vacuum advance, this should already be the case as MSD distributors generally come with a performance oriented vacuum advance canister. You can always limit it more if you need to.

Most bigger cams like as much initial advance (up to 20*) as you can run without hot cranking problems. Since you have a milder cam, that much advance isn't really necessary. I've never seen a performance engine that doesn't like 10-12* of initial advance. Now it becomes easy to select an advance stop bushing since it's just a mathematical calculation. 34*-12* = 22*. You'll want 22* of mechanical advance. In general, the MSD distributors come with 4 bushings, 28*, 25*, 21*, and 18*. They are Red Silver, Blue, and Black respectively. If you chose the Blue bushing, that would give you a maximum of 21* of mechanical advance. Running 13* initial would give you 34* total without vacuum advance (vacuum advance drops out at WOT since there is little to no vacuum at WOT) Here is the instructions for the bushings kit from MSD,

http://www.jegs.com/InstallationInstructions/100/121/121-8464.pdf

If you know how to use a dial back advance timing light, you can easily set up the initial timing and verify the total timing. One common mistake made is to set the initial timing with the lightest springs. The lightest springs can sometimes allow some mechanical advance at idle speeds. If you set your initial advance, you can find the total advance is off. Set the initial advance with the heaviest springs installed, and the engine idling as low as you can set it without stalling. This will ensure that you are setting the initial advance accurately. To check the total advance, it is easiest with the lightest springs because they let the weights fly out to maximum at the lowest RPM. You can mix and match the spring colors to get all your timing in between 2500 and 3000 RPM after you have set and checked the initial and total timing.

No one can tell you what is going to be optimal for your engine. Some testing and tuning is involved if you want to find out what works best. More info on Ignition timing here,

http://www.v8buick.com/showthread.php?63475-Power-Timing-your-Buick-V8

 

My pleasure. I wrote that Power Timing thread way back when. Ignition timing is a Frequently Asked Question. Glad I could help.