Buick 455 Camshaft Usage and Horsepower Ratings
By Dennis Manner, Senior Buick Engineer
In response to many questions concerning 455 engine camshafts and horsepower, there was only one factory produced Stage I camshaft used in 1969 400 and 1970-1974 455 Stage I Skylark GS Engines. This camshaft was identified by a single machined groove in the shank of the camshaft behind the front bearing journal.
The camshaft used in the 1971-72 Riviera GS and 73-74 Riviera GS Stage I engines was different than the Skylark GS Stage 1 cam and also different than the standard 455 engine cam. It provided more torque but a little less HP than the Skylark GS Stage 1 cam more appropriate for the heavier Riviera car. It can be identified by 3 machined grooves behind the front bearing journal.
The standard 455 engine as used in Skylark GS, Electra, Riviera, Wildcat or LeSabre models was the same engine (including camshaft) in any given model year. Four different camshafts were used in this engine in different years for non lead fuel/low compression engines in 1971 and later changes for fuel economy improvements as shown in the following chart.
Regarding confusion over HP ratings, the standard 1970 455 engine was rated at 370 HP in Electra, Wildcat, Riviera nd LeSabre Models. To allow the Skylark Gran Sport the best opportunity for "Factoring in Competition" we rated the Stage 1 at 360 HP at 5000 RPM.
To be comparable in the Skylark GS we also listed the standard 455 at 350 HP (to be lower than the Stage 1) although the engine was the same as used in Electra, Wildcat, Riviera and LeSabre Models. Hopefully, this will clarify the confusion among the enthusiasts.