I know headers is a over talked issue and Ive searched everywhere but still cant find this answer....putting on Exotic Muscle longtube headers on an LT4....is it hard to do? Do I have to cut or move anything around? Will it affect my emissions is the big question I have? What does it do to my cat converter? Thanks guys sorry for the headers junk.

 

Your stock cats are just beyond your current exhaust manifolds. They cannot be used with any long tube headers. You'll have to get some aftermarket converters to go behind the headers and have an exhaust shop hook everything together. Headers are not hard to put on these cars but getting the stock stuff off can often be a ton of fun. Sounds like you'd better enlist a friend with some experience to help you.

 

I just did the EM LTs on my 94 LT1 this past weekend. I used the Random Tech cats and a Corsa cat-back with them. Bolted right up with no problems. Merle at EM is a great guy to work with and he's a supporting vendor of the Forum.

Putting the plugs back in is a bit tricky because the tubes are about as tight as they can get. You'll need new plug wires as the stock ones for six and eight will be on the tubes. I used the Taylor Spiro Pros from Summit. They have a kit for the c4 with all 90 degree boots that are precut and fit well.

That's putting the new pieces in.

Getting the old stuff out as stated above is quite a joy. The manifolds, exhaust pipes, and mufflers are pretty easy, just time consuming and irritating as you have to remove a lot of stuff to get in there. Spray a lot of penetrant on all the bolts two nights in a row before you try and do it. Pulling one of the cats is the problem we had. I have a six speed and the one upper bolt for the cat bracket on the driver's side is a PITA.

We had to drop the trans down a few inches to get it out. Of course that requires removing the driveshaft which is fairly easy. But to get to the driveshaft you have to pull out the ladder. That is a lot of fun to do.

I wouldn't want to do it with the car just up on jack stands. You would probably have a problem getting enough leverage on some of the bolts to break them loose laying on your back. We did mine on a lift that a friend has in his garage.

Total time for 2 guys to do the headers, cats and cat back about 12 hours, not rushing and lining everything up perfect. That doesn't include the plug wires as I did them before hand.

System sounds great by the way. Sort of burblely at idle but sounds good when you hit it.

Good luck.

Oh, and the EM headers have the bungs welded on them already if you want to put the air tubes back in for the emissions stuff. The bungs are sealed when you get the headers but drilling them out would be easy enough. I didn't put that stuff back. We fabbed a plate for the back of the intake to block that off.

The random Tech cats accomodate two of the O2 sensors and EM sells a O2 simulator that fools the ECM for the other one. Works fine.

 

The emissions fittings were what gave me grief. Mine would not seperate from the manifolds. If I had it to do again, I would have purchased new ones and been done with it. They dont cost that much anyways. Oh and the right side tube had to be shortened about 1 in. I cut it and then got a brass compression union to put it back together. It slides under the fiberglass insulation boot so it cant be seen. The headers are time consuming to put on, but not that hard to do.