-T-

iTrader: (2)

I have an ls6 with stock lifters and valves. Upgraded to PRC dual springs and chrom hardened pushrod setup with my cam swap. Machine shop said my seat pressure was at 160# and I should be weary of the stock intake valves. What do the experts think?

vettenuts

iTrader: (4)

I have read of issues with high spring forces on those valves. Big question is why so heavy a spring, you are not taking advantage of the lightweight valves at all that could get by with a lot less spring force.

-T-

iTrader: (2)

Cam lift is .595"... Springs are good to .650 and very reliable. I didn't want to go with a .600 single spring and end up back in the motor. I've also read that these springs will soften up with usage. Think I should go bigger valves?

KCS

iTrader: (20)

What's the spring rate, or open pressure?

The most accurate way to meausre the spring pressures are to cycle them first. I forget the term for it, but you basically lube the springs up, and them compress them several times, and then measure. Same idea with bolts and torquing them several times before final torque is applied.

Once that is done, you may see a slight decrease in spring force, however, after a while, big losses in spring pressure means the spring is getting ready to fail.

vettenuts

iTrader: (4)

There are a couple of ways you could have gone. One is with a PAC 1518 or with a PSI 1511ML and shim to a smaller seat force. The springs you have are overkill in my opinion. Also, since the valves are light you don't need a huge seat value.