Trick Flow Heads: Conflicting Info on Mechanical Roller Spring Pressure

Mopar69gts said
To the op.
Howard's told me their rule of thumb on Solid Roller cams is,
100# per .100" of lift
So that's right where your at 660#
I used the pac 1225 spring
@ 2.000" installed height
It has 250# on the seat
And 675# open
With a .660" lift cam (after .020 lash.)
After a few runs they faded between
10-15#
Still turns 7,300 rpm for miles.
( Circle track. )

Thanks for the first-hand input. The 1225 is the 1200 series equivalent of the 1325 I calced out above. The 1300 series, according to PAC, is designed/produced for circle track endurance, resulting in a higher price than the 1225. It's good to hear that in your experience the spring rate was accurate and held up well.