408 ignition curver advice

Ooops
What is your curve like ?
My 410 stroker in my dustor has probably 11.4 to 1 compressiand and when it had a 267 at 50 duration with the 603 lift, I had about 12° of total timing with no vacuum advance and I would run it about 23 to thirty five and an extremely faster curve ... I think the MSD distributor had like the weakest Spring and the second weakest Spring in it....

I brought the duration of the cam down considerably to 245 at 50 (I think.. it's been a while..) and shaved the lift quite a bit... I left the distributor alone.. As long as I didn't get to punchy you with the pedal down low it ran much more predictable at lower rpm's...

Now the lower 9 and a 1/2 to 1 compression 408 I have in my truck. I have a 235 at 50 lift and a wide 18° curve with just the 2 medium Springs in the distributor. And it runs perfect from down low all the way out...