Welcome!

I tried installing a Pacesetter on my '87, but it wouldn't clear the motor mount. I'm told that the mount needs to be modded to be able to clear the header, but I think that brings the pipe too close to the rubber mount. Apparently, though, it's doable because people have done it ÔÇö I just didn't want to.

The big change in the exhaust system was in the 1987 model year. Prior to that the manifold had an integrated catalytic converter (a favorite Mitsubishi design), and everything downstream was different. For '87 that was changed to the familiar cast-iron header (you'll note it's actually a header and not just a manifold.) The engine didn't change, to the best of my knowledge.

Personally, I decided to search around for a stock manifold. If you're more comfortable with modding, then a Pacesetter could be a good choice. They are most definitely not a bolt-in affair.

As to the Weber, I've installed one and am still messing with it to get it "just right". Yes, you need to remove and plug every vacuum line/port on the engine, except for the one that goes to the distributor. That plugs into the valved vacuum port on the carb.

The only line to the air cleaner comes off the vapor canister, and it just connects to the elbow on the bottom of the Weber air cleaner. I'll take some pics for you tomorrow showing what I did.

One caution: the Weber absolutely needs a fuel pressure regulator. I went with a Holley adjustable low-pressure regulator, which has two outlets; I used one to mount a pressure gauge so I could dial it in exactly. I mounted it to a plate that I made to fit where the old vacuum control box was.