put a new msd opti in.. you can time it -/+ 7 degrees.. but i dont have a clue how to.. i have a timing light and everything. But weres the marks and all to time it. Also if i put a 50-100shot of nitous to it. dry kit what kinda timing wuold i wont.. its a stock Lt1 96 camaro.

 

The control needs to be set to "0", unless you have intentionally offset the cam sprocket on the cam. The big problem with the MSD is that there is no indication on the timing screw of where the "0" position is. I understand they are supposed to be at "0" with the screw 2 turns out, but you need to verify that with other MSD owners.

If you decide to spray nitrous, you don't change the timing at the distributor. Retarding it for the spray would reduce the perfromance without the spray. You tune it for optimum performance running NA, then use an external retard box to pull timing ONLY when you spray.

There are no timing marks on an LT1.

 

u think it would even be necessary to retard timing for a 50 dry shot?

 

Seems like a good idea to see where your timing actually is especially when using nitrous.

You could get some timing tape and install it on your stock damper.
A timing pointer (any SBC pointer for 7" to 8" diameter would be close enough).
Something like Allstar part number 90021...
or summit brand LINK

They come with 2 short bolts to bolt into a standard SBC front timing cover but that won't fit perfectly into the LT1 timing cover. So I just use one 4" bolt and bolt the timing pointer butted up tightly to the front of the opti-spark. I lay the pointer close to the LT1 damper but not so close that the belt cannot be installed. The pointer is pretty stable and secure by just that one bolt.

Find top dead center and line up the pointer.

verify timing with your timing light, (the PCM timing jumps around a bit so try to find an rpm that gives you a steady timng advance or load the motor by putting the tranny in gear on jackstands, or something). You'll need to monitor the PCM and see what commanded timing is.

I checked timing on an LT1 on an engine dyno recently and it was 2 deg. off from the PCM commanded timing as shown by Datamaster. (I forget if it was 2 deg advanced or retarded but I think it was advanced). That's not too bad. The motor had a stock GM optispark and the cam degreed dead nuts on.

Knowing exactly where your mechanical timing is is a good thing, especially when running nitrous because maybe your cam is one or two deg advanced and the opti is one or two deg. advanced and it stacks up to 4 deg. advanced, then your PCM tune is a bit agressive with the spark and now you are on the edge and then shoot some nitrous which greatly increases the flame speed of the fuel and then the motor get's a bit tight.....(and pistons crack).

Karl