Originally Posted by 2uraven
The nutter and rush did make a difference for my idle and starting but didnt seem to make any difference in response or on the top end. My timing was already at about 8*. I am not sure how nuttering makes any difference with an new ignition box installed. will start by rechecking my timing and plugs. when i had the engine rebuild i had them install an rv cam. do you suppose that would make a difference in terms of distributor gears if i decide to go with an hei already set up for the 258?
Can't tell all you have checked, so here are a few more suggestions:
Do the spark plug evaluation by running the engine under load (highway speed) and shutting down. Pull the plugs and read the color to tell if you are correct, rich or lean under that condition.
Pull the advance plate out of your distributor and check if it is the low or high total advance plate. If it is the low plate, you can file the slot and get more total advance when you need it.
Re-time to 12 degrees advance and check for pre-ignition. Adjust the timing down till no more spark knock.