tixeon

I am building a 383 using a 1 piece rear seal block. It will see street use only. Am putting in OEM hydraulic rollers on a mild cam(hot cam). 2.02 / 1.60 valves. Probably shift at 5500-6000 with that cam. I don't want too run too heavy a spring and cause extra wear and tear on a my daily driver. Patriot recommends an upgrade to 145 lbs seat and 375 lbs at 1.225". This sounds a little high to me. Dave

Solid LT1

My wife's 70LT-1 has 130# on the seat, 320 over the nose with a solid flat tappet cam your hydraulic roller shouldn't need to worry as much about too much pressure. I don't know what Patriot uses for spring manufacturer, basic Comp, Isky, Lunati, or Pac springs should work fine. Pressures recommended seem fine. Manley also has a good spring line.

gkull

Do you trust somebody Like AFR? AFR heads delivered 145# seat for use with a H-Roller cam. H-roller lifters are heavy recquiring good springs.

63mako

Hydraulic roller lifters are heavier than flat tappet. They need more seat pressure and higher spring rate to control the additional weight and faster ramp. Use the seat pressure and spring rate specified by the cam manufacturer for your specific cam. no more, no less. Don't let the head manufacturer spec your springs. They usually have 2 choices.

Edit: George beat me to it.