i would like to change bolt pattern on 1978 delta 88 from 4.5 to 5.5 i cant use adapters because the wheels hit when trying to turn i already got a price 4 getn wheels redrilled but was wondering if i could get rotors with that pattern that would fit or could i get my rotors redrilled with that pattern? any help would be appreciated!

 

It would be fairly easy to change from 4.5 to 5.0 bolt circle as wagons and heavy duty suspension cars came with 5.0 bolt circle.

Carmak
Riverside, Iowa

 

If you want to do this to use a certain set of wheels that you have, here's a tip. It will be cheaper and easier to sell the wheels you have and buy ones that fit.

First, your stock bolt pattern is 4.75", not 4.5". Second, as noted it's very easy to change to 5" since that was a factory option on these cars. There are no GM passenger cars with a 5.5" bolt circle.

Now, if you want to change to the 5" bolt circle to get the bigger brakes, you will need the following from a 1977-1996 B-body wagon, RWD C-body (Olds Ninety Eight, Buick Electra, etc), or B-body sedan with HD brakes (police/taxi):

Front spindles and rotors - the rotors with the 5" bolt circle are 12" in diameter vs. your stock 11" rotors. Since the caliper mounts are forged integrally with the spindles, you need both. This is a bolt-on change.

Rear axle shafts, backing plates, brake shoes, hardware, and drums. These must come from the same size axle as the one you have. These cars could have come with a 7.5", 8.5", or 8.75" ring gear and the axle shafts are not interchangeable. Also, the wagons use a wider rear axle than the sedans and those shafts do not swap. As an alternative to swapping the brakes and shafts, you can just swap the entire rear axle assembly. In fact, you can even swap in the rear axle from a 1991-1996 Caprice police car with disk brakes, though that will require the appropriate master cylinder.

Note that all the 1991-96 Caprices use the 5" bolt circle and the suspension parts are interchangeable with those on the 1977-1990 cars.

 

Just check out Summit or Jegs. There are plenty of aftermarket wheels that fit the 5x4.75" bolt pattern.

 

Go for the Correct Wheels and Tires for your Olds. Forget the re-drill and Parts change. Spend your $ on other goodies rather than make these wheels fit.
If your TIRES rub, that's a different problem.
There are MANY more Wheel Selections for the 4.75-5 than the 5.0
I have 5.0 on my 63 Olds 88 HC with Centerlines. They are great, but if I sell this car I am limited to few Buyers for these wheels.
Here's a link with a Calculator comparing Tire Size to what is Original to your Olds:
http://www.1010tires.com/TireSizeCalculator.asp

 

I know all the suspension and stuff was interchangable with the 91-96 Caprice, but what about the entire rear end? I know the Caprice's rear end in 91-96 was 1/2 inch wider than 77-90

Wasn't 4.5 x 5 a Mopar bolt pattern? I know the newer Mustangs (94+) use that BP and my Alero does too but the FWD version of 5 x 114.3