Valve springs 340 Stocker Engine

[Mike Coe]

Thanks for the reply John, see you in Vegas. Mike

[James L Miller]

Originally Posted by Mike Coe

Thanks for the replies.. Turbo, the reason the 1409X won't work is, the inside diameter of the spring is too small, I need at least 1.00 inch and when you squeeze that spring down to 1.680 installed height and then collapse it down .520 for cam lift and coil bind clearance it is at 1.16 and it says it coil binds at 1.19 inches. Mike

Sorry if I am ignorant on Stocker engine builds, but the spec I have for a 1969 340 calls for a .462" intake and .473" exhaust lift. Are people using a "square" lobe to loft the valvetrain off the lobe to get the .520" lift? I have an old Cam Dynamics 340 Stocker cam from the 1970s and it has a flattened nose on the lobes. I have some newer cams from Lunati and Bullet that have a more regular lobe appearance.

[Jim B]

Originally Posted by James L Miller

Sorry if I am ignorant on Stocker engine builds, but the spec I have for a 1969 340 calls for a .462" intake and .473" exhaust lift. Are people using a "square" lobe to loft the valvetrain off the lobe to get the .520" lift? I have an old Cam Dynamics 340 Stocker cam from the 1970s and it has a flattened nose on the lobes. I have some newer cams from Lunati and Bullet that have a more regular lobe appearance.

He did say the .520" number was for lift AND coil bind. Allowing .060" for coil bind clearance would put the lift number at about what you had....

[Greg Reimer 7376]

Originally Posted by James L Miller

Sorry if I am ignorant on Stocker engine builds, but the spec I have for a 1969 340 calls for a .462" intake and .473" exhaust lift. Are people using a "square" lobe to loft the valvetrain off the lobe to get the .520" lift? I have an old Cam Dynamics 340 Stocker cam from the 1970s and it has a flattened nose on the lobes. I have some newer cams from Lunati and Bullet that have a more regular lobe appearance.

The earlier cams had a more square nose profile like you describe because there was a maximum allowable duration rule in effect then.The valve started to open later,and it had to close sooner,so the lobe characteristics were more brutal. Parts breakage,valve bounce, bad stuff happened very frequently,especially on the go fast setups.The more recent stocker cams look more conventional because the ramp starts sooner,arrived at maximum lift about when it did, then closed later. Valve action was a bit smoother, and the engine would run at a higher rpm with out all that uncontrolled motion,Also,breathing started sooner and ceased later,making more power. DON'T EVEN THINK of using a square nose cam with a ceramic lifter. Get a set of Trend or Sherman tool steel lifters,fork out the bucks and do it right the first time.

[James L Miller]

I read that as ".520" lift" and the coil bind clearance on top of that. It never occurred to me that he was rolling the .060" in with the lift. In the USAF we had a saying about tunnel vision. Thanks for the vision outside my little box.

As far as that old CD Stocker cam, it sounds like it needs to go back in the 1970s box it came out of. I don't have the budget for ceramic lifters or even the tool steel ones. I think the Speed-Pro HT2011R lifters are exotic.