We haven't had a good BS session in a while.
I've been reading a lot about factory parts variances/manufacturing tolerances lately. The subject also came up in some Youtube videos and even during Drag Week.
It is interesting to hear that there are some pretty wide and acceptable ranges that will pass QC testing for the Big 3. Without going too far into it, my brother is a production engineer and does the validation for production line machinery. But, the kinds of things that slip through would astound some people. I am not just talking about casting, core shift or minor machining issues - rather things like cranks and cams ground with variables that would enhance or detract from vehicle performance.
I believe this is where certain cars out perform their assembly line sibilings simply because of a combination of the "right parts built wrong" coming together. Some of the discussions I have seen include cranks being ground off enough to impact where TDC lies, and then you can compound this with cams that are also ground a few degrees off; next thing you know you either have a dog or a racehorse in factory stock trim because suddenly the stock fuel/timing/airflow tables are less conservative.
Obviously this is where things like blueprinting or parts-bin hunting for 1-in-100 components that have favourable specs that can give a performance advantage in classes which require stock parts/part numbers.
I know in the case of the LS1 that came in our '02 Camaro, it had an LS6 block with better bank to bank breathing - which is worth an estimated 10hp over a standard LS1 block. But, this was simply a question of circumstance as the LS6 blocks were substituted as the LS1 blocks were unavailable (no real method to employing them). Regardless, we ended up with a very strong running car.
Anywho, we have seen this time and again where some cars just run harder than others right off the showroom floor.
