lost valve lift?

[FED 387]

has the low lift head deck surface been resurfaced a substantial amount?? try a 3rd head on the block see if maybe you cut that head more than you think you did also try checking all 3 heads on the other bank--- maybe when you decked the block you took off more on one side than the other --- try putting a straightedge on both the head surface and the block deck surface see if for some strange reason they are not flat - do not remember if you said you were checking with a head gasket--- might measure it in several places see if it is the same thickness at several points--look closely see if the rocker arm is hitting the v spring retainer --- I would try one head on both sides of the block see if there is the same variation then swap over 2 lifters then 2 pushrods see what happens---might try measuring EACH cylinder to see if the lift variation is consistent from one cylinder to another

[Jamie Greening]

It's all in the difference in spring pressure. Been there done that on a stocker cam. Always check lift with your spring that you are going to run. I thought I had a cam that was too big once because of checking springs. Had it redone for proper lift then once I installed my normal springs I lost the lift I had ground off.

[CFMCNC]

There will always be a loss at the valve going from a checking spring to a loaded valve train,One example cam card says 1.085 lift but after lash,bend and flex it was 1.013,another came card says 1.040 but NET was .977.This loss should be applied to spring height set up as it will affect coil bind.WE like to see .050-.100 to coil bind.Bill C.

[Mike Taylor 3601]

I would make sure that there is no binding of pushrod against guide plate,head etc where it has pushrod not seated in pushrod seat,like some others said when you have the full pressure of springs can lose lift.
If tip of valve is higher on your head that loses lift,that causes tip of valve and rocker stud to be closer,which puts tip of valve closer towards intake and roller of rocker out towards exhaust which is same as reducing rocker ratio.
Mike Taylor 3601