what was the first month the LS6 chevelle was produced? I've heard the earliest was september of 1970 is this true, anybody know for sure?

I'm sure you meant the year 1969 as cars were being built prior to the actual model year. From what I found - mr, a TC member has once stated in a post that the 1st known, documented 1970 Chevelle SS LS-6 was built at Baltimore, December 9, 1969. greg 2001 also states second week of Dec 1969. Do a search on "LS6" on the forums and you will find an extraordinary amount of information.

There is a GM letter stating that the L78 would be phased out in Nov. 69. The last publically known and documented L78 was produced on Dec 8th, 1969. The first publically known and documented LS-6 was the following day, Dec 9th, 1969.

I have heard of earlier supposed documented Nov, 1969 LS6's and have seen the documents of some of these supposed real cars and they were fake. Until someone comes up with real documentation of an earlier car, it would stand at Dec. 9th. There are earlier magazine LS-6 feature cars but it is widely assumed these were converted L78 cars to test and use to introduce the new drivetrain.
Rick