ask the person that you got the setup from what it was setup for.

 

Ditto on the pr length. Wrong length can lead to disasterous results like rr hitting keepers and dropping a valve. I'd check for the correct length befor messing with the rockers. JMHO

 

Hmmm......CC306 huh?
You're pushing it with that combo. The CC306 yields .544/.576 lift w/1.6 ratio rockers, and the max valve lift you should have using those rockers is
.575. I have no idea if that's "really" the problem, but I'm sure GM put that in the instructions for a reason.

 

I did not know that about the rockers... good point.

now can some one please tell me how I can test pushrod length if the rocker doesn't go on the stud enough to put a poly lock on. I haven't even tried pushrods yet on the unaltered rockers so I know that is not the problem as to why they don't fit... am I going to need different pushrods when all said and done? yea 90% sure.

the reason I asked about stud length is because is the stubs were a half inch longer I could put them on with only having to grind down the tips a little.

after doing some searching on summit I found a set of proform rockers. I think they are GMPP ones seeing that proform=gm. I think.

these rockers would not work though do to spring diameter.


spring diameter is 1.460 and the keeper is a slightly larger than this. the rockers only support 1.500. so with the keepers being alittle bigger and only having .040 clearance anyway I think that may be the problem.

maybe I should take pictures cause think there is some confusion on what I'm asking seeing as everyone says pushrod and I don't see how something that hasn't even been put into the assembly yet could cause that issue.

 

Crane makes the GMPP rockers.

The max spring diameter for those rockers is 1.450", which is really strange because the suggested valve spring to be used with the rockers is 1.460" in diameter (according to Summit Racing website).

What I gather from what you're saying is that the underbody of the rocker hits the retainer before the roller tip will touch the valve. Pics would help. If that is the case though, you probably would be better off using something like a Comp Pro Magnum rocker that supports using those larger diameter valve springs.

 

that is it. dead on. New rockers it is then.

 

I have the 1:6 crane gold race s/a with isky springs and had to change my valve retainers to step up .010 valve stem for rockers to touch valve stem it was the head assembly place fault

 

I do also think you need to look at pushrod length, but yeah, the GMPP rockers definitely do not support using that large diameter springs. I have those rockers, but my springs are 1.430" diameter. Let us know how things turn out.