I have built a 340 and a 440 with eldlebrock heads over 10 years ago and both are still running great. I remember reading both heads required adjustable rocker arms.

That is so you can set the correct pre load or valve lash depending on what kind of cam your running.

It is rare that you can just bolt on non adjustable rockers after changing heads and cam and have the proper pre load or lash.

Pre load and lash are two different things too.

If you insist on non adjustable rockers then in most cases you have to have custom push rods which is much tougher to get right than just using adjustable rockers to get your pre load right on each lifter. Custom push rods means there all not going to be the same length.

The pre load on a hydralic cam should be set before you install the intake manifold so you can see what your doing on each lifter.

Good luck. If you wiped a cam lope than you need to take the motor out of the car and all the way apart to clean it out.