Those who have the AS&M headers how did you like the fit and how was the plug access on them ?

 

These headers require a lot if patience and creativity to get them to fit correct, out of the box is not good from what I have heard. Spark plug access is horrible on #5 and the entire right side.

I will explain the issues you can expect.
1. The header flange bolt holes will not line up perfectly with the bolt holes in the heads. You will have to force the bolts to thread because of this. Be prepared to enlarge and tweak the flange holes cause you dint want the bolts binding in the least when installing them into the head. This involved installing them and removing them several times which is a PITA but worth it in the end. When I was done I could thread the bolts in completely by hand, this ensures a good seat and no leaks or potential of bolts seizing up. This entire process can be made much easier if you have a 2nd pair of heads off the car. I have also heard that this bolt alignment issue can be found in nearly every other brand of headers. Don't skip this procedure.

2. The driver side header 1st primary will hit the u-jointed steering shaft. This is what I did. I separated the steering shaft and shortened it 3/4". I then welded it up solid. By doing this the shaft is raised a good bit from the shaft and there was no more rubbing. I also removed the bolt securing the bottom of the steering column to the fire wall. I then enlarged the holes so I could shift the bottom of the column about 1/4" further to the passenger side. This gave me even more distance from the steering shaft. I have never come close to rubbing the shaft with these mods. Some people think you may be able to install a LS1 steering shaft but I cant confirm this, if you did this you will definitely require an alignment cause the shaft indexes differently.

3. You will need to lower the rear brake line where it come close to the driver side header. This involves bending the line which is easy to do.

4. You will need to put a bend in the pipe coming from the driver side header that goes into the Y because it will hit the oil pan. This will involve heating the pipe with an oxy-acetylene and bending it about an inch or so. I bolted this pipe to a block of wood , heated it and lifted it upward. This will again involve trial and error to get it right. You will also damage the ceramic coating right at the bend of the pipe. Its no big deal, I fixed it with POR20 high temp silver paint. You definitely want to bend it at the bend in the pipe. This will provide plenty clearance at the oil pan.

5. You will also need to grind an access hole in the K-member to allow tool access for the top most flange mounting nut. This hole does not hurt anything and will be about 1/2" in size. Without this hole you will not be able to get a socket on this nut unless you are a magician.

6. You will need to grind a small area of the right side k-member because the passenger side header flange will be hitting it. This is vary easy to do with a disk grinder and will not hurt anything by doing so.

7. You will need to weld the included 3 hole 3" flange on you existing catalytic converter, this would be a good time to just purchase a new 3" universal high flow cat.

I am confident that anyone who goes to install Rk sport headers will run into these issues which must be addressed. THEY WILL NOT BOLT ON PERFECTLY DIRECTLY OUT OF THE BOX WITH NO TWEAKS.


I have RK sport's which are a AS&M knock off, they are nearly the same and have the exact same fitment issues. Once they are tweaked and installed correctly they are an excellent header with 1.75" primaries and you don't lose any ground clearance plus you can easily switch out your catalytic converter to a test pipe or something eles. These are the best performing headers just short of LT's.