Well I had true dual exhaust, longtube hedmans, and dual mufflers. I'm trying to tuck the exhaust up since the roads where I'm living now are fairly awful. My question is would running the headers into a Y pipe then having a single cat near the driveshaft. This would give me over an inch more of ground clearance than I currently have and would help me all around- but will it still get hot enough to work effectively? It's only a 18" or so further than the stock cat location so I'm hoping it won't be a problem.

 

Technically, the cats need to be where the factory put them. Your area may or may not quibble with that, but that's what the Federal law says.

They lose effectiveness as temp goes down, which is why the factory puts them so close to the exhaust manifold.

On the other hand, you may be able to measure/calculate the distance from the exhaust ports to the cat inlet on a factory system and show yours isn't any farther away.

But, that may not buy you anything, because it says "location", not "distance".

Besides, longtubes don't have the A.I.R. tubes, so wouldn't be legal, anyway, unless you added them one way or another.

 

Just gotta pass the sniffer, not visual.