Try using the weakest springs you can get in there
I use the Mr. Gasket 925B spring kits in most of the Mopar distributors I use in Hi Po street and race only cars, I shorten up the advance slots so I have between 14 to 18 degrees at a low idle RPM and all the timing in before 2000 RPM. I really concentrate on having no more than 34 to 36 degrees total timing, higher altitude use 36, lower, below 2000 FT above sea level, I use 34 total
I also verify my timing tab and balancers when assembling the motors to make sure I'm getting what I see with the timing light and timing marks