I'm getting close to dyno tuning my new 383 (read: year old, 7k miles) for the first time and there is a question concerning the discrepancy between what is in the timing tables of LT1 edit and what is reported by Datamaster. I remember that this subject had come up in the past, but at the time I wasn't paying much attention (that'll teach me!). Currently, my timing in the 90, 95, and 100kpa levels are 35 degrees to 36 degrees. This is actually quite close to my stock file. When scanning via datamaster starting around 5k, the timing is reported as ~39 and continues to increase to 41 degrees at 7k. So not only is there an initial discrepancy (offset?) of ~3-4 degrees, but it's not linear! So my question is, which value do I believe and use while trying to find the optimum timing for WOT power? This has really been confusing me for awhile now. If I remember correctly, the general consensus was that there was an additional factor or table that isn't accessible with LT1 edit causing the difference. So is my engine currently running 36 degrees above 4k as reported in LT1 edit, or is it really climbing to 41 degrees by 7k?

Thanks in advance!