core 'revision' number...BS? BUSTED!!
Sure could be. They probably started pouring at least a couple months before a new release. There is a lot of fine tuning to get things right for a production run on a new part like that. It's a pretty complicated process. 273's and 318's had been around for a few years and had been tweaked already.
They do 'pilot builds' at different stages of the design process before production...
There is usually one in Jan-Feb, and another build in April-May, just before launch to prove out the tooling is making good parts...
The Jan-Feb build is about a couple dozen and all of the vehicles go to the different design groups and vehicle development to test the cars to make sure that they meet the requirements... Including a few that go to the proving grounds to put miles on them to see how they hold up....
The same thing happens with the build in May... Those cars go to each of the different design groups and the proving grounds to put as many miles on them before launch to find any defects/problems... The pilot cars are usually driven 16 - 24 hours at the proving grounds to try to put 10,000 - 12,000 miles on them ASAP before the launch in June/July....
Any parts that are not off of production tooling in the May pilot must get a TSA (temporary substitution approval) to use a production quality prototype part and are placed on a tracking list... As soon as the production tooled part is available, they will then phase it into the build slowly at first until it is proven to be ready....
If they can't make the part properly and can't use a prototype tool, then that part/system is put on hold and not available in production until they get things in order... Like the shaker hoods for the 70 Challenger... They weren't ready for launch and they substituted the dual scoop R/T hood until the shaker hood tooling could be completed.... They don't want to stop building the car completely, but just restrict the components that are late... In extreme cases, they will push back the launch 3 -6 months if needed....
The Jan-Feb build has a few prototype parts and mostly production parts as they are available... The April-May build is supposed to be all off of production tooling...
