[Steve C.]

"...reprofile or replace your cam with gentler lobes and soften up your valve springs some."

My application is currently street only but that's what I ended up doing about two years ago after a roller lifter failure. At the time I was running a aggressive UltraDyne MSP roller with 0.709" lift in conjunction with PAC 1243 springs rated 240 on the seat.

The new cams intake lobe we used had the same .050" duration but less aggress, or less intensity, depending on the wording. I worked with Tim at Bullet Racing Cams and with that lobe he said years ago they used to run it with a typical Small Block Chevy valvetrain mass with around 190 lbs seat pressure, and in a Big Block Chevy mass at around 220 pounds if memory serves me right. Tim suggested in a Pontiac at the 190 lbs. But keep in mind these numbers were from 30+ years ago and I don't know what type parts were used.

I choose a spring rated 220 lbs at 1.900, knowing it will lose pressure after run in. That and my intake valves are a larger 2.150" diameter and with a longer stem length for that 1.900" installed height. It tested 205-210 lbs after the dyno session with my LSM on the head spring tester.

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