I installed a comp 280 xfi cam on my smallblock 383 chevy.The motor has etec 200 heads(springs good to 600 lift)18ccdish pistons3.75rods.I was running a TPIS zz9 cam 515/555 lift on 112 base circle.NOw i have a comp 280xfi on a 113 with 576/571 the duration is 230/236 at 50.The cam calls for beehive springs comp part#26986-16. To start the motor i used the stock Etec 200 springs.I tried Adjusting the rockers I tried everything from 1 half turn to 1 full turn from ZERo lash.The motor runs good,At idle i have no noIse but when i rev it i here a loud tapping right under my intake.With the zz9 i had no valvetrain noise> im stumped IT cant be the lifters can it

 

Anybody?

 

If your valvesprings dont have sufficient pressure you can bounce the valves off the seats. This causes all kinds of valvetrain noise.

 

If you figure this out, let me know... I have an XFI268 and I've adjusted my Comp Cams Magnum rockers (roller tips) several times and the chatter won't go away.