Recently put a .508 mopar performance cam and hyd. lifters, previous cam was .484 and now we have loud noisy lifters/pushrods/rocker arms. Any suggestions??  

Did you do an accurate check of your piston to valve clearance? If your clearance was too close, when you fire it up the hyd lifters will pump up and push your valves right into your pistons. Good luck.  

Check to make sure the rockers shafts are not installed upside down, if they are your rockers will not be getting enough oil which will cause the noise your discribing.
The shafts need to be mounted with the oil holes down towards the rockers.  

Oil holes down toward the valve springs, But I know what you meant.

Dart340
If you didn't soak the lifters in oil over night they will make noise for a lot of that 25-30 minute break in period. I like 2200-3000 for at least 25 minutes.
What part # spring are you using?
Are the heads stock?  

i recently put in the same camshaft and my 340 it too is noisy, lifters seem to be leaking down after we adjust them. any suggestions on how to tell if its the lifters or the camshaft, everything is new, very frustrating, my valve to piston clearence is ok thanks  

Most cam manufactures no longer recommend soaking the lifter in oil over night.  Did you check lifter pre load ?