when he says they are non adjustable he means that they are "designed" to be tightened to twenty and forget about it. if you are looking for more performance then you can do it differently.
"This assumes the rest of the engine can live at the increased speed, and that increased RPM might help performance. We have found that the larger Pontiac engines generally run quicker when shifted at a relatively low RPM."
his "sequence" can be used with stock valvetrain as well as crazy solid roller cams. If your engine is stock, which is what i keep seeing everybody recomend ( 068, 068, 068, blah, blah, blah) then tighten them like factory and walk away. if you are looking for more and your engine can take it then do them his way. or disregard years of R&D and dyno time and do it your way.
When you tighten them all down to 20 lbs you are assuming that all the lifters are in the middle of there travel. When you hot lash them, when running you back off til they clack, tighten til they don't clack and then 1/4 turn. Then you know that all the lifters are adjusted exactly the same and it frees the valve train up and won't float the valves as early as it would in the torque down mode. For my base line I turn the motor 1/4 turn at a time, tighten all loose rockers until the push rod gets light pressure between the rocker and lifter, rotate it another 1/4 turn and tighten again, continue until all pushrods have been adjusted, start it then hotlash it. That is the easiest way to do it and works for me and not much thinking. Also, if one valve on a cylinder is open, you can adjust the other knowing it's on the flat of the cam. I would run SBC lock nuts as stated in the article, that is cheap insurance so the nut doesn't back off at an inopertune time.
The lifter actually has 1 full turn of adjustment and you can fine tune your cam with it. The guys running 1/4 turn at the rocker will get a few more rpms before the valves float with a little less bottom end. Best for high speed runs.
Running at 1/2 turn will slightly increase valve lift helping bottom end at the expense of a lower red line. I don't rev that hard and am more looking for bottom end grunt so I run at the 1/2 turn on the rockers. I would not recomend more then 1/2 turn.
I haven't lost any bottom end with the 1/4 turn, but at a 1/4 turn they will need adjusting sooner with wear, or bad oil. Bottom end is all about advance curve kits in your distributor. Back in 82, in highschool with my 455 66 Tempest, I put a set of Sorrenson cross cut points and an advance curve kit in. With the heavy springs it dogged out of the hole, with the light springs it was a tire shreader, all the diference in the world. I don't know what todays gas will do with all the initial advance, ping like hell I suppose. Pontiacs make power down low, so all in worked and made a lot of power. I was a hero in highschool with my 2 barrel 455 with a 70 GTO rear w/3.55 gears, that car smoked almost everyone I came up against, but I didn't race grown ups with "real" cars.
Oh, that reminds me, maybe I have a kill story for the other thread, funny as hell. Or, I'll give the cliff note version here:
1984, Buddy had a 70 442 w/455, paid $1000 for it, me, 66 Tempest 455, paid $450, we are on a 3 lane going to the capital in Madison, 70 Cutlass pulls up between us with a full roll cage and two mid 20's guys in it (grown ups), drag strip ready. Game on, light turns green and my buddy and I both smoked the Cutlass and left him by a couple car lengths, my buddy nosed me. Guys in the Cutlass didn't even look at us at the next light, guess there 350 with a cam was no match for CID!!
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