16th Jan 2016, 18:52

The feedback carb on the 307 is the venerable Rochester quadrajet and requires almost no maintenance. Every now and then the choke needs to be adjusted - that's it. The mixture and idle speed are computer controlled and the mixture screws are sealed off. If the 307 develops driveability problems, it's usually other things causing the computer to alter the carb mixture and not the carb itself causing the problem. Common culprits are vacuum leaks, EGR malfunction related to failed EGR valves and exhaust leaks causing the EGR valve not to function properly, blocked EGR passages, dirty air filter, and improperly set ignition timing.

The 307 is not powerful, so expect leisurely acceleration with 0-60 in 13-15 seconds. The Olds 98 is a great old reliable cruiser and makes a great daily driver if you don't mind being seen in an old land yacht. Put some snow tires on it and it'll be a fantastic winter beater. 250,000 miles on the stock powertrain is not uncommon for these tanks.

17th Jan 2016, 05:20

Excellent review!!!

The bumper fillers are an ass pain.

Make sure the cruise control servo holds vacuum. Underhood heat (which Oldsmobiles are great at generating) which deteriorates rubber bellows can render servos inoperative.

You'll do fine with the THM 200-4R transmission as long you keep up with (yearly) fluid/filter changes. If it has made it this far, it is likely one of the better units built from that time frame :)

The flat-tappet 307 is a decent motor. You'll need to replace water pumps, and keep an eye on intake manifold gaskets - aluminum intake manifolds combined with cast iron heads make for coolant leaks. Again, frequent fluid/filter changes work well. I never saw a road test comparing the Flat-Tappet/Low-Swirl Head 1980-1984 engines vs. the Roller-Tappet/High-Swirl Head engines.

Fun fact: The 1985 Oldsmobile V8s did NOT require premium fuel. The also-revamped-for-1985 Chrysler High-Swirl Head 318 V8 could accept regular fuel, bit LIKED premium fuel.


21st Jan 2016, 14:15

I'm the first commenter. Saw an 83 Olds 98 2 door. 70,000 miles. Beautiful car, love the long low silhouette and the gorgeous velour interior. Engine runs smoothly. But the chassis had constant rattles and noises while under way. Couldn't tell if it was front/back right/left, but definitely not from the interior. This car had passed the provincial safety inspection, which means that things like ball joints, tie rods, bushings, shocks, springs, frame would have to be in safe condition. Also I was disappointed by the harshness of the ride as bumps in the road produced lots of jolts. I know an Olds 98 should be smoother, quieter and more isolated, so I didn't purchase it. Any ideas? I know that tracking down chassis noises is difficult. Would I be looking at a complete front end and suspension re-build?

22nd Jan 2016, 03:47

Rubber body mounts may be dry rotted.

22nd Jan 2016, 23:52

Anything is possible with a car this old. Bad tires can cause a car to ride terrible. Those state safety inspections have minimal safety requirements.

12th Feb 2016, 05:19

Original reviewer here.

I've never heard of a professional road test being conducted involving the two 307 motor variants. Most likely, many did not know about the change at the time, as GM never advertised the swirl-port heads and roller lifters, because they probably hoped that these changes wouldn't noticeably affect performance. People probably found out once they began to service their cars and dealers/parts stores began to tell owners about the difference.

Having driven both 307 motor versions, I can say that the difference in actual power between the two isn't really that great (both have the exact same paper figures though); however, the early-1980s flat-tappet motor will feel a little stronger because it's not so RPM restricted like the 1985-1990 swirl-port motor is. This makes a noticeable difference because the later motors always ran out of power at higher RPM (you didn't even have to rev it up much to do that).

Another point of note, the Oldsmobile 307 had even more power in 1980-1981 (148-150 hp and 250 lb-ft of torque), virtually on par with the Chevy 305. In 1982, power was cut back to 140 hp, but torque was slightly bumped up to 255 lb-ft. This first power reduction was likely a move to meet CAFE and emissions requirements. Then in 1985 came the roller lifters and swirl port heads, which didn't affect power ratings, but it affected air intake (which was already bad on these engines to begin with), which in turn affected driveability. Again, this was to meet emissions and to slightly boost fuel economy ratings (GM was crazy back in the 1980s about saving every drop of fuel).