David, when the guy looks at the beginning and total timing, you might also have him look at when that timing comes in. Diff cams and carbs ask for timing at diff times. That is why I spent 100 bucks to have the dist recurved for my applications on both the CS and the Cobra. As well, when the fellow does the recurve he can look at the dist lobes. On our small block for our CS, a couple of the dist cam lobes were off as much as 6 degrees. In short, if you look down at the timing and lets say you have 13 degrees initial. Two of my cylinders were firing 6 degrees off of that. We went through 3 diff dist b4 we found a good distributor that had less that 2 degree error on the dist cam lobes. It makes a big diff.
If you are runnning a vacume advance, look at when the vacume advances the timing. Two of the Dist we had required a huge amount of vacume to get the timing advanced. We ended up using an old Vacume advance unit for our CS because it required less vacume to advance the timing.
So, three things on the Dist that will give/take HP/Tq. The weight settings that allow the advanced timing to come in at certain RPM. The lobes on the Dist being in sync, and the vacume if you are running a vacume advance.
Oh on the carb. From the factory, Holley is bad about putting a stiff spring in the vacume secondaries. I dont remember how the street avenger does it, but something for you to check. The original spring for our secondary advance in the current carb we have on the CS wud not begin to open the secondaries until we reached between 3 and 3500 rpm. They were not totally open till we got to over 5500. The reason they do that is to keep the car as a 2v for as long as is possible to give better MPG. However, does not do much for your off the line performance. We switched the springs (kits are available) in our 600 and the secondaries now begin to open at about 2k, fully open at 4500.
Diff cams and carb settings require advance in the timing at diff times. As well, needed that fuel for bottom end hp and TQ. Fun to watch on a Dyno.
Brian