Sorry for the million questions but the more we have the better the answers...
How long have the valve springs been in there?
Were they changed for the new larger cam?
What are you running for spring pressures over the nose? Is that what Bullet recommended?
Who's springs?
The .560 actual lift... is that after lash as measured at the retainer, or that's the advertised lift and not measured at the retainer?
What year block is it?
What heads?
What machining (that you know of) was done to the heads and deck?
What head gasket?
I am not necessarilly saying "longer is better". More that "different might be better". In terms of the threads... Especially with an aluminum rocker, you want to keep the force running in the direction the rocker and adjuster are designed to transmit it. You lose lift and duration having too many threads showing, and as the rocker moves through it's travel the force ends up going through more of an angle. That means at the point of greatest spring pressure, the force is pushing sideways and up on the adjuster. The further out the socket, the more stress on the adjuster (think the end of a lever and it's fulcrum point). It's not a big deal stress wise if the engine is basically a street one with mild pressures. But when you start talking about 370+ and some rpms, you dramatically increase the risk of breaking something and you lose a tiny percentage of power because of the angles and parasitic friction loss. So I'm a firm believer in having 1-2 threads showing and no more. The last part I order is always the pushrods because until it's all together and everything is accounted for, the length is almost a guess. Well for me it would be a guess without the checking pushrods.
These are my J heads, w/11/32 valve stems and about stock mopar installed height 1.920 or something, can't remember.
the springs came from engle but are manley part#'s
140-145int lbs and 335 open@.550
tip wear is just off center towards the exhaust, just a lil.
If I remember right I'm losing .029 lift form what I should have w/ a 1.6=.589 before lash.
I can't remember if it was .560 after or before lash, I will check it.
Another good one is when I bought the bushed mp rockers they advertised as 1.5, but when I tried both the 1.5 mp and 1.6 alum rockers, there was only a .005 diff in lift at least on the 1 I checked....
So now I will be measuring the rockers to see what the hell the MP's really are and if the adv 1.6 aluminum rocker is really just a true 1.5
that aside, I have 1 to zero threads underneath the rocker and 2 above the nut.
78 or 79 block, squared, torque plated, .040 over, heads milled to 62cc .020 off of 1 and .040 off the other to get there, that outta make up for sum length.
