Sounds like your Distributor is not set up for a stroker. Sounds like you had that dizzy curved for a 340/360 and just used it on this one. Strokers like alot more Initial Timing than 16*. Reason I say this is I had Don curve diffferent dizzy's for different set ups and the one you are describing is for a Non Stroked motor. His Dizzy's done for a 410 of mine was Initial 23* with 11* mechanical "34* Total" built into it all in by 2400 RPM......I bet your car is pretty lazy down low.