[HWYSTR455]

Nothing makes a Pontiac different than any other V8 pushrod engine, the same principals apply. If you get different readings from rocker to rocker, than it's an issue with the rockers.

If there's a difference with the distance of the centerline of the rocker stud to the distance to the valve centerline, the issue is with the head. No manufacturer would design a head with different distance. (some exceptions apply, like with porcupine heads, and that's only between intake/exhaust, not from one intake to the next intake for example).

It's like saying distance is different from distributor cap to distributor cap between posts, it's just not so. If it is, it's a problem with the cap.

If you have questions as to how to properly do a half-lift method adjustment, don't take anyone's word from it here, look it up. Compare from example to example, and you will see the common factors.

This isn't that complicated, in the end, the pattern will tell you if it's optimum or not.

And the sweep should be slightly more towards the stud when correct, with the narrowest sweep.

Adding lash adjustment after the initial check in general is a preference, .020 for a HYD or .025 for a solid isn't going to make a big when pushrods are in .050 increments, you go one way or the other, it's not a substantial amount to cause and drastic change. Keep it simple.

If the cam is on the base circle then you count the poly lock turns, if you have the lobe at half lift you need to use a checker spring for either a HYD or solid, and you don't need to count the turns, you just screw the ploy lock down to take all the slack out.

It would be pretty hard to turn the adjusting pushrod to take up the slack if the lobe is at half lift, you would have to compress the spring, and usually adjustable pushrods are flimsy and could deflect from the spring psi.

If you have the lobe at half lift and you add the calculated turns to the poly lock for another half lift value it would simulate being at full lift.

There are literally 100s of youtube vids on the subject, watch a few, it will become obvious how to do it.

Just to throw a twist in though if you want to get anal about it, between the base circle and the lobe starts to actually lift, there is a slight dip where it is less than base circle, but for the most part it's not enough to take into consideration when measuring for rocker geometry. (But it can be a consideration when adjusting lash, which is why EO-IC method is preferred.).

Reference, @8:40 min mark: https://www.youtube.com/watch?v=USBHPOA2akY&t=769s

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