I have 2 question riviera 72 gs have the same engine that the 71 gs ? if not which is the differense between the 2 ? thanks
71 and 72 both run a 8.5:1 compression ratio. Don't get fooled by the new HP ratings: The 72 is a wee bit off in the power department due to the tighter emission rules.......:Smarty: '71 GS was 270 SAE net HP, '72 GS was 265 SAE net HP.
The performance of the 72 and 73 model dropped dramaticaly cause of emissions regs. The 455 was choked to just 225 hp (standard) and 260 hp (GS) instead of 315 hp (330 hp for the GS) in 1971. For the looks and great performance 1971 was th year, especially the 1971 Riviera GS is a collectible automobile. Bumper regs bloated curb weight to 4500 pounds for 1973. This power to weight handicap conspired with the radical looks and slashed sales. The 1972 model still had the looks but performance was not that good anymore compared to 1971. For 1973 the Riviera had just the roof line and window I'm confuse whit people say that the last performance riv was the 71
The horsepower ratings for the 71 Riv GS are 265 net and 330 gross. This is from the 1971 Buick Facts Book. For 72 the horsepower rating is only shown net and thats 260 for the Riv GS. Looks like a 5 horsepower drop, not a huge difference.
