(Car Craft Magazine refers to the B4C as a 1LE equipped with air conditioning; although this is slightly erroneous because in 1991, the large brakes with PBR calipers from the 1LE package were not included with B4C.) Just under 600 B4C Camaros were sold for 1991. Power ratings on the 350 TPI were as follows; at 4,400 rpm and at 3,200 rpm. Power rating on the 305 TPI motor were as follows; at 4,200 rpm and at 3,200 rpm. Power rating on the 305 TBI stayed same at 170 hp(127 kW) at 4,000 rpm and 255 lb⋅ft (346 N⋅m) at 2,400 rpm. Rumors say that these numbers were slightly underrated by GM, but this has not been investigated. Beginning with the 1991 model year, GM pioneered some modified assembly techniques with the F-body Camaro and Firebird which were carried forward into the fourth generation. Different seam sealers, structural adhesives, and body assembly techniques were employed in key areas in an effort to reduce squeaks and rattles and improve the perception of quality. The SCCA Showroom-Stock-ready 1LE package continued with similar equipment to previous years and was again triggered automatically by the G92 Performance Axle option combined with the C41 basic ventilation system (no air conditioning) on the Z28 coupe. Production of the 1LE increased to 478 units. 1992 1992 was the final year of the third generation Camaro. A "25th Anniversary Heritage Edition" option had been planned with Corvette aluminum cylinder heads, tubular exhaust headers, and 6-speed manual transmission, but this was scrapped in favor of a "Heritage Package" option (RPO Z03) which amounted to nothing more than a graphics package of badges and rally stripes. All 1992 Camaros received a "25th Anniversary" badge on the dashboard. The 1992 version of the Camaro B4C (Special Service Package) got the addition of 1LE brakes. A total of 589 B4Cs were sold. The B4C option was also deemed popular enough to be carried on to the fourth-generation model. Some TPI 1992 Camaros received some of the "leftovers" from its Corvette cousin, which switched from Tuned Port Injection to the new LT1 engine series in 1992. They received the rough texture, cast aluminum style, intake runners from the TPI Corvette instead of the regular Camaro smooth tube ones. In some cases, they were built with black painted valve covers instead of the normal silver valve covers. Some also received a blank throttlebody plate,