It's all there in the post. READ.
Proper valvetrain setup is usually done wrong on the LS engines because it takes time, effort, and knowledge. Even most of the knowledgeable guys are STILL doing it wrong. But even wrong they are forgiving enough to still run well.
There are two different "LS7" lifters, one being superior to the other, and each likes a different preload. ALWAYS use the 12576400 lifter, and set it to 0.060" max. Again, for most LS setups 0.060" is still too much.
well here is the issue with the part numbers that you list for being the different preload and I have come across ,lots of superseded numbers for the lifters ,, it sounds like it could be a place of manufacturing.. the only way to find out what you have is to get each part number lifer and disassemble them to compare the specs ,, so if any one has one of the part number lifers ,take them a part and measure, also measure complete travel and bleed hole location
the part number that I used was 12499225 and crosses to all the numbers below SOOOOOOOOOO, if any has a spec sheet for each of the posted lifter part numbers ,please post them .. I am interested
on a another note on the dod delete with the ls3 cam swap I fabricated some mid pipes (no cats and turned off the second o2 sensors ),, motor is real quiet and performs great with real noticeable seat of the pants performance ,, hits the chip much faster in first gear ,, on my way to the 11.99 time slip
see below for the part numbers in qusetion
Made by OEM supplier General Motors Components Holdings (formerly Delphi)
These are same as the GMPP and LS7 lifters except that they are purchased in bulk so the are not individually boxed
Equivalent to GM part number 17122490 (ACDelco part # HL124).
GMPP part number 12499225 is just 16 of part # 17122490 packaged into a set of 16 pieces
Also compatible with GM part number 12576400 (HL128