By the way, J heads were phased in during 1970 model year,and not just on AAR's and T/A's. They had 2.02 intakes etc. Some argue that the J's flow marginally better, but from what I have seen it is a wash.

The earliest 340 4bbl J heads that I have seen are dated October 1969. I am always looking for older dates, I have been trying to figure out when they started using them in 1970. If anyone has pictures of earlier non -T/A J heads please send me a picture. Thanks.