We are building an 82 pro street car but are putting 85 front end on it with the ground effects. Question is, will an 85 impact bar bolt up to an 82? Thank you!

It should. People change the bumper covers all the time without issue. Really the 85 front should go on without changing the impact bar.

No you have to change the impact bar to the 85-up one. There is just enough difference to not let the nose fit right. The bar might be the same but pretty sure the honeycomb that is mounted to it that is the issue.

By the book there are four impact bumper part numbers 82-86. Now the question you have to ask is what's the difference? The book doesn't really say. At least this half of the book doesn't say, and I honestly don't feel like pulling out the 3-ring binders to see if the other half explains what's different. What I can say is I've seen a lot of early cars with later bumper covers that were put together by people that would never think to change the impact bar. I'd expect the differences between the three part numbers include at least one version that's aluminum, and might include things that are as minor as having the holes drilled to mount the fog lights.

So then does the impact bumper need to be changed? Maybe. If it does it'll should bolt right on.

YUP. The same thing is true when dealing with the rear impact bar; the honeycomb is different on Coupe, IROC style, & 90-92 Z28 style.