systems of the period and later the addition of heavy federally mandated bumpers. 1971 The 1971 Camaro received only minor appearance changes from its 1970 counterpart. Inside, new high-back Strato bucket seats with built-in headrests replaced the 1970-only low-back seats with adjustable headrests. The biggest changes came under the hood, due to a GM-corporate mandate that all engines be designed to run on lower-octane regular-leaded, low-lead, or unleaded gasoline, necessitating reductions in compression ratios and horsepower ratings. The straight-6, V8, and two-barrel V8 were virtually unchanged, as they were low-compression regular-fuel engines in 1970 and previous years. The LT-1 350 V8 used in the Z/28 dropped from 360 hp SAE gross to SAE gross due to a compression ratio decrease from 11.0:1 to 10.3:1. The 350 c.i. engine in the 1971 Camaro Z28 produced SAE net. The 396 (402 c.i.) V8 dropped from 350 to SAE gross due to compression ratio drop from 10.25:1 to 8.5:1. The 402 c.i. engine in the 1971 Camaro SS 396 produced SAE net. Production and sales dropped due to a 67-day corporate-wide strike at GM that coincided with the introduction of the 1971 models in late September 1970, along with a continued declining interest in the ponycar market fueled by skyrocketing insurance rates for high-performance cars. Rumors of the possible cancellation of the Camaro after 1972 began to surface and were nearly confirmed a year later when another worker's strike hit the assembly plant at Norwood, Ohio, which was the only plant building Camaros and Firebirds. 1972 The 1972 Camaro suffered two major setbacks. The UAW strike at a GM assembly plant in Norwood disrupted production for 174 days, and 1,100 incomplete Camaros had to be scrapped because they could not meet 1973 federal bumper safety standards. Some at GM seriously considered dropping the Camaro and Firebird altogether, particularly while the corporation was under pressure to adapt its vast number of makes and models to difficult new regulations for emissions, safety, and fuel economy. Others pointed out the fiercely loyal followings the cars enjoyed and were convinced the models remained viable. The latter group eventually convinced those in favor of dropping the F-cars to reconsider, and Chevrolet would go on to produce 68,656 Camaros in 1972. Only 970 SS 396s were produced in 1972, and this was the last year for the SS 396 and SS 350 models, as well as the last year