[blykins]

Don't forget, you need a .060" locator/cup. Your install height then goes down to roughly 1.700". With a .630" lift, you still don't have much room....

Now, you could potentially go with a +.050" lock, which would put you up to 1.750", but with .630" lift, you're still trying to find a spring that will coil bind at around 1.050-1.060".

You could also skip the +.050" locks and go with a +.100" retainer, like a tool steel retainer or titanium retainer.

[CROCIE JR]

Longer valves to gain installed height is not where I would go. More of a last resort. To keep actual valve train geometry in check you will need a longer push rod. This is assuming the geometry is correct to begin with. Longer push rods move the rocker up the stud. This gives less engagement for the Poly lock. You will be in the 150 seat 420 lb open territory. I would want at least .550" worth of stud above the trunnion. Sonic check the spring seats and go as deep as your machinist is comfortable. With thos springs .080 to water with a hard cup, is as close as I would go. I think with your short valves and a +.050" lock and retainer you could get to 1.78". So .140" off the spring seat, sounds a little scary. Sonic check first. BTW most 1.65 rockers are more like 1.7+