Valvetrain question
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Valvetrain question
What is the recommended margin between the stated valve spring max lift and a cam's lobe lift?
I messed-up and ordered a different cam than what I had intended to.
The valve springs have a stated max lift of 0.600 and the cam I got has a lift of 0.600. I will be using 1.7 ratio rockers.
I have next to nothing of information on the valve springs other than they are PAC dual springs. I have asked for the coil bind number.
I am going to attempt to measure installed height as the heads are not installed.
Trying to determine if this setup will work and have a long life; mild street driving; or I need to exchange the cam.
Appreciate it.
Also, the cam I thought I ordered has a 0.550 lift, so only 0.050 less than the cam I got.
I tried to measure installed height, but due to the recess was not able to get an accurate measurement.
Best guess would be installed height of 1.800.
I think these are PAC 1900 series dual springs, which states a max cam lift of 0.625. If this is correct, then I might be okay with the cam I have.
The heads are from Summit Racing, their LS6 (AFR) head and that is where the 0.600 max cam lift number comes from.
Trying to decide if it is worth the cost and time to ship the 0.600 cam back and get the 0.550 cam. I just do not know what that 0.050 lift difference is going make.
I messed-up and ordered a different cam than what I had intended to.
The valve springs have a stated max lift of 0.600 and the cam I got has a lift of 0.600. I will be using 1.7 ratio rockers.
I have next to nothing of information on the valve springs other than they are PAC dual springs. I have asked for the coil bind number.
I am going to attempt to measure installed height as the heads are not installed.
Trying to determine if this setup will work and have a long life; mild street driving; or I need to exchange the cam.
Appreciate it.
Also, the cam I thought I ordered has a 0.550 lift, so only 0.050 less than the cam I got.
I tried to measure installed height, but due to the recess was not able to get an accurate measurement.
Best guess would be installed height of 1.800.
I think these are PAC 1900 series dual springs, which states a max cam lift of 0.625. If this is correct, then I might be okay with the cam I have.
The heads are from Summit Racing, their LS6 (AFR) head and that is where the 0.600 max cam lift number comes from.
Trying to decide if it is worth the cost and time to ship the 0.600 cam back and get the 0.550 cam. I just do not know what that 0.050 lift difference is going make.
Last edited by LannyL81; Mar 13, 2025 at 06:12 PM.
