I agree they do drop compression, but as stated the cam and a ton of timing can make it run and use only the 87 octane. ran a 15.7 with a set of 3.55s and a stock 318 with headers and cast iron intake with a TQ off a lean burn engine. the cam was stock with a lousy set of 360 heads that had terrible guides. But it ran consistant in a car that had a 4300 lb racing weight