Just teasin ya about Cumby's car.I know through conversing with you in the past,you are fully aware of what he has.
"What configuration of left smog tubes are the top restored LS-6 Chevelles using with and w/o cowl induction"....
Most are putting on the over the valve cover tube even if it's not accurate for their early build,but either design will fit fine when Cowl Ind. equipped or not.
I believe it is due to owners not knowing there was a design difference & revision date for this tube,(as noted in the 1970 Chevelle Ass. manual),as well as most reproduction houses only carry the later issued over the valve cover design tube anyway.