milled heads

.050 is no big deal, but correct hyd lifter preload and rocker geometry need to be kept in spec. When the heads get new valves, or a valve job, these can also be thrown out of whack. You know you're milling .050 off, so you'll need to mill at least .050 off the intkae..Not the intkae surface of the heads..the intake itself. Reason? Your valve cover gasket head flange, is what you're milling off, to make the manifold fit. Any more than .030 off this flange, is asking for leak problems later. So now you need to have a "fits one cyl head combo only" intake made...It's around $50 to have that done around here. So, now the intake fits, and the heads are bolted on (leave the intake off)..Try tightening down on the rocker shaft with the pushrods in place they ones that are on the cam ramps (valves opened) wont go all the way down. You've bottomed out the lifters....you can see this in the way the plunger is way down int he lifter body..using a set of wire feler gages, you can measure the amount of space between the plunger and the retainign clip inside the lifter body. Safe bet, you'll need to shorten the pushrods by at least .050". Comp Cams offers these, as do others, that are designed for factry style staped rocker arms. They cost about $125. The alternative, is as mentionned, adjustable rockers, and cheaper new pushrods with cups for the rockers. Together, $70+$199 (add $199 aluminum rockers arent worth $100...not worth bothering with IMO) The rock bottom cheapest way is to use shims under the rocker shafts. But, dotn think that .050" worth of shims is perfect. They might be, but the only way to get it "right" is to measure the preload. Aim for .030-.040" per lifter. Shims will go $30 a pack or so, and you'll need 2 boxes I think. So, at minimum, you have $60 in shims, and $50 in extra milling to make it all fit. Also, it's the grunge way out, dont rely on it revving to 6500 on a regular basis...lol.