1st Oct 2010, 12:14
Because the engine in this car has virtually no passing power and terribly slow hill climbing power. The reviewer is correct about the 1985 and newer 307 V8 being worse than the 1980-1984 version. I once owned a 1985 Delta 88 with this motor. Loved the style of the car, hated the ultra slow acceleration and lack of performance. The motor is a total boat anchor, almost as bad as the smaller Oldsmobile 260 V8.
I do not feel the need to burn the tires up at every stoplight, but at least some decent acceleration is nice to have.
If the car is in good enough shape, I recommend ripping out the 307 and going with a Buick, Chevy, or Oldsmobile 350, or even doing a 455 Buick or Olds big block conversion, which doesn't require too much modification.
3rd Mar 2011, 19:55
I feel the pain of the original poster. I bought a 1986 Buick Regal Limited Coupe that "unknown to me" has the post-1984 detuned Oldsmbolie 307 V8 (if one could believe detuning an already tepid motor was possible). One would think all Oldsmobile 307's are the same, but I found out the hard way that they are not.
The cylinder heads on the wimpier 307 are stamped "7A" on the front outer corner, Instead of the "5A" on the older more powerful versions. The 7A motor was even used in the 4000+ pound Cadillac Brougham and a lot of full size GM wagons until 1990. The camshaft does not lift the valves high enough on the 7A, and the intake and exhaust ports are too small, making for an engine that can't breath above 3000 RPM's.
I've been trying to kill the 307 in my 1986 Buick by beating it to death, but at over 200,000 miles, it still won't die.