1978 Oldsmobile 98 LS from North America - Comments

Note - These are all the repaired items from 84,000 miles to 210,000 (and still kicking)

At 126,000 - radiator, timing chain set, master cylinder, rear wheel cylinders.

Idler arm and upper ball joints about 160,000.

Transmission re-build at 174,000.

Water pump.

Alternator at 150,000.

Starter at 140,000.

AC clutch at 150,000.

Rear end at 210,000.

I will miss this car when it finally does die, but I am not sure when that will be. I think the body will rust in half first and I like in Tennessee.

At 210,000 miles the engine is just as strong as it was at 84,000. The car was purchased by my father at 84,000 miles. He gave it to me at 126,000 because he had neglected it and did not want to fix it anymore. I gave it the TLC it needed and proceeded to drive the wheels off.

All of the repairs I listed are pretty typical of ANY car and are VERY reasonable when you consider the mileage figures they occurred at.

The thing starts and runs no matter what the conditions are and I have never been afraid to take it on long trips.

The best part - 403 cubes of V8 power. It sucks down the gas, but moves pretty good for a boat.

The Olds 403 was a destroked version of their 455 which was discontinued in '77 (which is just as well as it was watered down quiet a bit- 400hp in top form in '68, 215hp in '76)

The 403 is not a de-stroked 455. It is a bored out 350/307 block. It has a shorter deck than the 455. It has the largest bore of any V8 to date. The cylinder bores are "siamesed", they are so big.

The horsepower rating is low, but the torque is fair. This is the same engine used in the TransAm 6.6ltr (non T/A version). It was the GM corporate 6.6ltr during 77-78-79.

For information regarding increasing the output, see the website by Joe Mondello regarding modifications to Oldsmobile engines.

In 72 the compression ratios for the 455 and other engines were dropped from 10-11:1 to 8:1. The heads also got hardened seals for unleaded gas. Oil embargo and Greenpeace converged on Detroit at about the same time.

I have a 1988 Olds Custom Cruiser Station Wagon. It is the same body as the 77 and up Olds full size rwd cars. It has a 307 and runs great. One day it will be replaced with a 403 long-block, as a simple direct bolt in replacement. Recon is a rebuilder company which sells the long-block for @$2,200.

You are all wrong, the 403 was made from a 403 block. Plans to use the 350s and 455s were ruled out because of all the problems they had.

"You are all wrong, the 403 was made from a 403 block. Plans to use the 350s and 455s were ruled out because of all the problems they had."

Nope, you're wrong.

The 350 V8 had no problems. Olds was forced to drop the 455 (another awesome engine) in 1977 due to CAFE fuel economy standards.

The 403 was essentially a Oldsmobile 350 with larger (4.351") pistons, compared to the 350's (4.057 inch diameter) pistons. I believe it actually did have the biggest diameter pistons of any V8 to go in an American passenger car.

All of Oldsmobiles final V8 engines had the same block and same stroke length (3.385 inches). There were no water jackets between the pistons on the 403, which at times led to overheating problems. The 350 (gas), 307, and 260 were not as powerful but much more reliable than the 403.

The 403 was not a bad motor, but as with all V8's of the mid to late 1970's it was choked to death with silly emission regulations, tiny intake and exhaust ports combined with low compression from the start. With it's short stroke and huge bore, the 403 engine could have been a real powerhouse. Original and aftermarket parts are scarce for the 403, while the 350 and 455 are some very sought after motors.

Oldsmobiles 350 is a much more sought after motor. It was simple, reliable, strong, and very economical for its size.

It is also a little more powerful than the Chevy 350 of that era, and far better than the Buick 350. And for those who didn't know: yes Oldsmobile, Chevy, Pontiac, and Buick made there own smallblock 350's back then, completely different from one another.

I own a 1978 Delta 88 with a Olds 350 that still is capable of over 21 MPG highway with the old TH350 3 speed automatic. 223,000 miles, doesn't burn a drop of oil, and still runs like a swiss watch after 31 years.

FYI, the formula to find the cubic inches of any motor: (bore x bore) x stroke x.7854 x number of cylinders.

Also the Oldsmobile 350 was the standard motor in the 1977-1979 Oldsmobile Ninety-Eight.