resdoggie

I did.

augiedoggy

Im just going by all the research I was doing up to my purchase a few weeks ago... I could see how things like damaged/compressed body mounts and sagging springs and even things like iron heads vs aluminum along with other weight changes could effect this.

regardless though unless the fenders are physically different allowing different clearance from year to year (pretty sure your 76 has identically sized wheel wells and fenders as my 74) I would think the other things could be addressed without major modifications such as cutting fenders. I saw people with a variety of different years stating they worked over and over which is why I went with them myself. I made sticky notes and tallied up the different combos. there are also a lot of people running 18x8 wheels with the 4" bs and 245 wheels its just about the most common setup on the 18" wheel thread. They should be more forgiving than the larger 255 wheels and wider 8.5" wheels im running.

Now you have peaked my interest im always working on my uncles 76.. maybe ill try one of my wheels on his to check fitment.

skibber

Front susp done bout 20k mi. ago.

skibber

I considered trimming the fender and might have but it would have been visible from the front of the car.

resdoggie

I believe the fenders were trimmed at the factory when they went to 255's in '78???

augiedoggy

Again my 74 does not have any fender trimming or mods and they fit so thats not the issue and would be the best way to approach this...

Its got to be the suspension. Chances are its the fact that my suspension is original and tired that allows the 255/45 tires and 8.5" wide rims to fit without rubbing as mentioned earlier by the person who said they cut their springs for more clearance.

skibber

Yup. I could see how that would make a difference.

resdoggie

I believe I found a part of my problem - the entire body of the car is about a 1/4" more to the right of the centerline of the frame. There is nothing to indicate that it has shifted so I assume it left the factory that way. It became very visible when I put on my new wheels. A recent alignment confirms my frame is straight and square.

7T1vette

There are literally hundreds of part tolerances that are in play when analyzing the wheel fit in the wheelwell. So there is quite a bit of variation between individual cars. That's why some folks are able to put 255's on (but only about half of them) but almost everyone can install 235's. Just the way it is.

And, yes, GM opened up the wheelwells by more than 1.5" in 1978...just so they could guarantee installation of [optional] 255's.