I have fastburn 383 heads with a XE 268 flat tappet cam. I put on some summit 1.6 rr and I have some bad noise. I adjusted the valve lash (running) 4 times and nothing has changed. The rockers keep ticking no matter how far I adjust them down. This engine is relatively new (5000 miles) and I after I changed the cam I checked the push rod length like 5 times. Right now I'm running hardened 7.75" pushrods and before the cam I was running 8" (with no noise). I also have pushrod guides because the summit rr are non-self aligning. Today I seen that the rockers are barely touching the guides, how do I get the rockers up higher? I'm getting really frustrated because I tried adjusting these rockers so many times and I always get the same noise. The heads are stock with no modifications. Thanks for any help in advance.

 

You might be binding the springs. Are you still running stock springs?

 

they're still the stock springs. I thought the stock springs were rated higher than my lift .520". Do you really believe they're binding? If so is there an indicator? I just went to gm performance and found that I need to change the screw in studs to another type that accepts guide plates. I'll order them and change them over when they get here. Hopefully this is the cause of what I'm experiencing.

 

you need to trash the stock springs. you can adjust the guide plates to get closer to the push rod.

 

The springs can handle up to .56 lift, being that the installed heighth is 1.78 and the binding heighth is 1.22. I calculated my cams lift with my 1.6 rr and it comes out to .512. The difference between my lift and the max lift is roughly .05, which is around a 1/16". I would think this would be enough space and I was even told (by others on this board) that I shouldn't have a problem as long as I give a safety margin (no larger lift than .520). Thanks for the replies so far, but I'm going to put the other studs in and see what happens. I'm not sure if the noise is the rockers hitting the guides or what. I'm half tempted to just put the 8" push rods back in (from when the valvetrain was quiet) and see what happens. I remember that when I checked the geometry then, the index mark on the stem wasn't too far from where it is now.

 

it doesn't matter what you calculated the factory springs need to be trashed and won't work for .56 lift.