Well Just got done with heads cam swap on my Z. Decided to go with comp 850 lifters. Not the 875 which are the type R's and are crap for a street car, to little preload. Well got the swap all done put the lifters in and checked preload. Well stock is .060 - .120max. Mine was a turn and a half of the rocker bolt after 0 preload to torque to 22 ft lbs. This equaled out to .090 right withing O.E. specs. As comp claims this is an O.E. lifter (original equipment replacement) and did not include any directions I set them to stock specs and ran with it. For about 50 miles. The valvetrain was very quiet at first, but then gradually got louder and louder. So I called comp. They first said install it to stock specs, :screwy: The next tech said only .030 - .050 preload, YIKES!!!!! This equals 1/2 - 3/4 max turn on the rocker bolt after 0 preload. Well I gave them hell for calling thier product a stock replacement if it didnt meet stock preload settings. They told me to get 7.35 pushrods and run the motor in neutral to 3000 rpm for 5 minutes to pump up the lifters again. WHAT!!!! I do not think I have a collapsed lifter, Its not that loud yet But we will see when I get my pushrods in. Just wanted to let everyone know that the standard excuse of LOUD valvetrain due to cam swap, may be preload Adj. or no comp cams instructions. :mah: Oh stock lifters preload was almost 2 full turns of the rocker bolt.