Actually, Chip's Atlas had a whole new cockpit design installed prior to the 1983 season. The original(1982) had Chip sitting in a seat that was actually above the level of the deck and Chip was surrounded by what amounted to a wind screen made of FG. After the "rework" of the cockpit, Chip's seat was lowered by almost 6", was more form fitting and he was strapped in with a five point harness, surrounded by two inches of aluminum honeycomb.
Most of the boats in the early 1970s had the botttom seat pad just below deck level and in front of the rear of the cockpit, giving the look of the driver sitting forward when, in actuality, the driver was pushing himself into the seat back to hold himself in the boat. In fact, AFAIK, the only boat with a rear cockpit that had a seat belt was the 7325 Pay'N Pak, but not until after Ron Snyder was thrown from the boat in Evansville during the second heat of the 1986 race