I'm still fine tuning my motor in and trying to get it right and I want to re check my timing now that I have access to a timing light. Here is my setup. Rebuilt 96 vortec 350, gm hei distributer with vacuum advance , 95 lt1 camshaft. If I understand correctly I need a base timing of 8-12* timing, and an advanced timing from 32-36* timing. So if I'm right here are my steps and correct me if I'm wrong. I need to start the car, take the vacuum line off my dizzy and plug it, loosen my dizzy hold down and connect my timing light to my battery and number 1 spark plug, check timing and move dizzy till I'm between 8-10*. After I'm there tighten down the dizzy, reconnect vacuum line to dizzy, and rrcheck timing and it should be around 32-36* timing. If correct remove the timing light and adjust the idle screw on the carb. Am I correct or missing steps?

Base timing is best set depending on the cam grind. Your 95 LT1 camshaft has around 202 duration @ 0.050" lift. All the base timing that cam needs is 8-10*.

Once the base timing is set, you never have to move the distributor again however you will need to play with the weights and springs inside the distributor to achieve a proper total timing. Base timing plus mechanical timing equals the total. How much total timing you need depends on what exactly the engine wants. 32-36 is a ballpark number. Some cars may want lower, others may want higher. Unless the timing marks have been degreed in, they're not very accurate and may be out a few degrees so your exact numbers may be out to lunch but if that's where the engine makes it's most power, go with it. Putting the engine/car on a dyno, you can play with the timing to see what total makes the most power. On a dragstrip, you make multiple passes and keep track of MPH changes. The best total timing will make the most MPH.

The distributor should be at full advance by 3000 rpm. The weights control how much mechanical advance you have, the springs control how fast it occurs. You can mix and match the weights and springs to fine tune the timing curve.

An advance timing light works the best because you only need to watch the TDC mark and adjust the light to line it up instead of numbers and marks on the balancer. At an idle, the engine should be at the base timing. As rpms are increased, the timing will advance. If the distributor is set up properly, the timing shouldn't advance any higher over 3000 rpm. If it does, change the springs to bring the curve in faster. Like I said, you can mix and match so if one light and one heavy spring works the best then that's what you use. Once the speed of the curve is established, play with different weights to set the total timing. Start low with 32*. Go make some dragstrip passes. For a quick and simple adjustment instead of playing with the weights, readjust the distributor a few more degrees off the base timing and see if the engine likes it. When MPH starts to drop off, you've gone past where the engine like the total timing.

If you started at 32* and by 38* you started making less MPH then around 36 is probably the optimal setting. Readjust the base timing again and play with the weights until the total reaches 36* again then recheck to make sure the springs are controlling the curve to be all in around 3000 rpm.

Vacuum advance is for part throttle operation. You only need it for driving on the street and isn't factored into a distributor performance tune.

You may need to adjust the idle mixture screws when the base timing is changed but don't play with jetting until the distributor curve is figured out.

The can in the car has a spec of 205/207/117. Where can I get different springs and weights for adjusting the distributer or do I do it with the ones already inside it? And are my steps for setting base timing correct?

heres a good video that might help?

i personally tune to full advance. dont really care what initial is, as long as its within reason. i agree,...test and tune is alot of the proper setting. just gotta experiment some.

My stock compression/vortec heads/xr276hr motor didn't make any noticeable power gains between 32-36 (IIRC).

Trouble with EFI systems is the knock sensor. Advance your timing to try and get more power and if the engine starts to get some preignition, the knock sensor picks it up and the ECM retards the timing reducing any gain you were trying to achieve.

That's also why people claim to make more power with a higher octane fuel and EFI. Less detonation, less retarded time, more power.