It's been a while since I've checked in here, so I don't know if anyone even remembers me, but I'm an old member from back in the day. I still have one of my thirgens, and recently ran into an issue that peaked my curiosity.

Ok so the car is a 1990 Camaro RS. It originally came with an L05 TBI 305. About 11 or 12 years ago with the help of two friends I put in an L98 350 TPI from a 1988 GTA. At this point some of the details of the swap are a bit hazy, and admitedly I was not the brains of the operation. In fact I was only present for maybe 75% of the work, so while I certainly got my hands dirty I can't claim to know everything that transpired.

I drove the car for a year or two tops, and then it sat, and sat, and sat for about 8 years total. In 2011 I put it back on the road, and while it needed quite a bit of work to get it running again I did not replace the serpentine belt at that time.

Now if you are still with me we have reached the point of this post. I have no idea what parts of the serpentine belt system are from the donor car, or what parts are original to my car. As far as I knew all 88-92 serpentine systems were the same, but apparently they are not. I purchased a new belt a few days ago for a 90 Camaro that was 94.5 inches long. Unfortunately the old belt on the car proved to be 98 inches. I headed back to the auto parts store, and they looked up a 1988 model, which did in fact call for a 98 inch belt. So apparently while a 90 F-body takes a 94.5 inch belt, an '88 takes the longer 98 inch belt.

So does anyone know what might be different between these two years? My best guess is a difference size pulley, maybe on the power steering pump?

 

Couldn't tell you the difference but it probably is a pulley. I'd almost want to say on a motor swap it would probably be the crank pulley but who knows for sure. A difference in 4" sounds a bit excessive for any pulley.

As long as you know your car takes a 98" belt and you can bring in any (future) broken accessories to the auto parts store it shouldn't matter.

 

Oh I'm not worried about it. It's just more curiosity than anything. You might be right about the crank pulley. We probably didn't swap that out. That makes a lot of sense.