I'm feed up. Time to ask for help!

Are they open or closed chamber Eddies? Flat top pistons, but how far down the hole? How thick is the head gasket?

The orange box I had came with an electronic ignition conversion kit I bought from Summit Racing. When I plotted out the timing I was seeing the orange box back out 10 degrees of timing after 3500 RPM. The 35 degrees I thought I had turned into 25 degrees after 3500 RPM.

Bottom line is you need to run the RPM up to 4000+ to be sure the total timing is staying constant.

If you would have asked me a year ago what is the ideal timing for a SB Mopar I would have quickly responded 35 total. I ran a 340 back in the day and that was where it was happiest. Fast forward to the 360 I am running now with closed chamber EQ Magnum heads and thin .028 head gaskets. Granted, the factory cast, dished pistons are .088 down the hole and I am only netting 8.7:1 compression, but unless you measured it you don't really know where you are.

During a test and tune I played with the timing and was surprised at the results. My distributor has 22 degrees of mechanical advance and I original started with 16.5 degrees initial for 38.5 degrees total. I fully expected the car to slow down if I advanced the timing any more.

Initial Total ET 1/4 MPH
16.5 38.5 13.31 101.52
18.0 40.0 13.28 101.86
20.0 42.0 13.23 102.58
22.0 44.0 13.32 102.34

The magic number ended up being 20.5 degrees initial or 42.5 total.

In this case I might be more cautious to start and begin testing at 34 degrees total. I would then try 36 and see what the MPH tell me. If it liked 36, then try 38. If the MPH slowed going to 38, then I would try 37.

For comparison I run a 3500 stall converter (904) with 3.91 gears and 27" tall street tire (255R17)