Power piston spring

[77cutlass]

Which power piston spring do I use, there are four in cliff's kit, would the longest one be okay for a stock motor with high vacuum?(21 inches at 550rpm(in drive)

[FNG]

you want to use the strongest spring you can that will still pull down pp with the vacum you have.i have 18 in vac in my 461 pontiac i used the blue spring in cliffs kit works great.i think that one was one of the longer/stronger springs.