hydraulic lifter problems

Can you go to a taller tire? like a 27 or 28" tire....that will get the trap RPM down. Are your pushrods the right length giving you the right pre-load? I used to run an Edelbrock RPM cam with th eEdelbrock lifters and my 318 would run up to 6300RPM without a problem. You might be having a problem with coil bind with the 1.6 rockers....have you check for that.....that's a lot of lift to be running with stock valveguides and retainers.