I'm right in the middle of installing 1-7/8 ARH LTs w/cats. The stock header gaskets are two part thin metal. The ARH set came with a different type of gasket material. It's about 1/8" thick soft silver metallic (not sure what material it is). I've read that the stock gaskets can be reused. The ARH instructions don't state whether the ones they provided are intended to be used no matter what or only if the stock ones get damaged. If the ARH provided gaskets were the same as stock, there'd be no question - but since they're totally different, I'm nervous about using them.

Has anyone installed ARH 1-7/8 with the stock gaskets and experienced no leaks? Can I just clean them up with a soft wire brush (they look really good) or should I use the new material that ARH provided?

 

I used the arh gaskets with no issues

 

Same here

 

Far be it from me to reinvent the wheel. I followed your lead, took all the bolts back out and swapped the gaskets for the ARH provided ones. A little more aggravation, but didn't take that long.

Another question; sorry for being so naive, but I've never messed with headers before. The stock header flange is a flare to flare with a donut shaped gasket in between. The ARH is a ball and flare. I'm assuming that no gasket whatsoever is used in this joint. Am I correct?

 

No gasket between the 2, just tighten the bolts really well.

 

Correct, no gasket Drive around for a hundred miles or so then get under there and tighten them up again...THEN your good to go

 

Yes, I've seen several posts by TOM and he is very knowledgable. I just thought this route would be quicker since I know there alot of you guys out there that have done this mod yourself and I needed an answer quickly. Nick (owner of ARH) told me to call if I needed help, but naturally it's Saturday night and no one is there to answer the phone (I actually did try to call them).

Thanks for all your help. It's all in place. Just came in to check my service manual for torque numbers for the header bolts. Except for having to get the car up higher on jackstands than I've ever done before, this was not as difficult as I thought it would be.

 

the arh should gaskets be round and the stock should be rectangle port shaped. best to use the fbody mls gaskets since they are reusedable, where arh are kinda 1 use.

 

I used ARH gaskets ... two years, 20K miles, no issues.

Have you fired it up yet?

 

I finished putting everything under the hood back together and fired it up this morning. At first there was a rattling/buzzing sound like something was loose, but after everything warmed up it stopped. I double checked all the bolts and everything feels tight but not sure what it was. The tone is definitely deeper than before. Also it sounds like I hear air rushing from the S/C whereas before my V3 SQ was so quiet you couldn't hear it at all. I'll call my tuner tomorrow morning to see how quickly he can get me in for a re-tune. My boost gauge shows that the vacuum in the intake is less by about 4 or 5 "Hg (expected) so hopefully I'll be able to pull the restrictor plate out of the intake.

Lessons learned;

* Instructions tell you some things that need to be removed, but here's what I removed (or disconnected and bent out of the way as necessary); FRCs, air tube (metal) on drivers side, pulled vacuum line off brake booster, fuel line (firewall to fuel rail), plug wires, plugs, coil packs, cables on back of generator, battery, plastic battery shield, catch can, dip stick tube, rubber tube from coolant reservoir, starter, front wheels.
* Generator did NOT have to be removed. I've read some people remove theirs and I was really dreading that because it would have required loosening the serpentine belt and with the S/C, gettting the belt back on is a major PITA.
* I took the front wheels off and would definitely do it again. If you're working from jack stands, you'll be crawling under that area every few mintures and with the tires removed there is ALOT more room.
* I wound up removing the drivers side wheel well access panel that closes out the cove area. I wound up dropping about a dozen things during this install and they all fall out there. BTW, when I first opened it, I found one of the coil pack studs that my tuner shop had obviously dropped and never retrieved (and just left out of the coil pack), one of the rubber udders from the bottom of the cowl (did you know there are 3 of them on the drivers side), and a few other lost items.
* The ARH instructions said to remove the passenger side air tube by loosening the rear attachment bolt. I've been there, done that, no way again (requires removal of the intake manifold). So I took the two bolts out and just bent the metal tube up to the rocker cover to get it out of the way. After installing the headers I had to put two screwdrivers into the bolt holes to bend it back to an orientation that would bolt up. Actually, it appeared to me that there was going to be some bending required anyway because the stock air tube flange is straight toward the center of the car, but the ARH air tube flange is angled upwared (just like the drivers side).
* Use the ARH provided gaskets - don't reuse stock.
* 22" high on jack stands (measured from the floor to the bottom of the rocker) was plenty high enough and I'm convinced it would have been possible several inches lower because I had no issues with ground clearance whatsoever.
* Starter removal highly recommended.
* Ground strap on drivers side had to be disconnected from the frame rail under the washer reservoir.
* Must reposition the HO2 connectors after install because the ARH sensor bung is too far downstream for the connector to be put back into original location. It would also be melted because one of the primaries would wind up touching it even if it would reach. I just tucked them upward between the firewall and the bell housing (hope they stay).
* I put the HO2 sensors in after inserting the primaries up through the opening. Originally I mounted a few of the bolts but they had to come back out to get enough clearance down low to get the HO2 sensors installed. It might have been possible to mount the sensors before inserting the primaries up through the opening but I didn't try that.
* Even with the starter removed and all the wires pushed back, I still got one of the wires hung on the primary flange and skinned the wire up a bit. You must make sure those wires are clearing the flange as you go up.
* I've read several posts where people had trouble getting the headers up through the opening, so I made sure to prep everything I could think of and had no trouble at all. In fact both sides went in in less than 30 seconds. ARH is correct. Once you find the right orientation, they slip right in.
* On both sides of the bell housing there is a plastic baffle that sticks out about 1/4". Nick had told me to cut this off because it often causes trouble for people. I used a coping saw and did both sides before even attempting to put the primaries in. It took a few minutes but was easy to cut. I don't know whether it would have actually been a problem or not, but one thing is for sure - if it's not there, it's not in the way.
* Nick had warned me about the a/c line being a problem too. I actually used a mallet to bend the line all the way up against the frame rail (immediately behind the compressor). I've read several posts of people stating that it would take more "persuasion" that you would initially feel comfortable with, but that the tubing would bend and be ok, so I just whacked it a few times and it bent right over, no problem.
* Once you insert the passenger primary into the opening, you must get the starter back on and all the wires attached. Once you push the header up high enough to get bolts in, you have no room at all to do the starter.
* The dip stick tube must be pulled out. Initially I tried to leave it in place and work the stock header primaries around without moving it, but it came out anyway. No big deal, it sticks in with an oring at the bottom. However, I noticed after the ARH headers were in place, the dip stick tube was touching one of the primaries. I figured that would get really hot, so I used a screwdriver and slightly increased the bend radius right by the primary. Now theres about 1/8" clearance. Likely will still get very hot, but at least it's not touching.
* ARH gives you a couple of cable clips (metal with rubber coating) to try and mount the cables for the rear HO2 sensors up to one of the tunnel plate bolts. One of the cables was long enough to do this, the other was not. It is TIGHT trying to do this. I wound up doing only the longer one, moved both stock clips about 1/2" higher up and bent the heat shield outward. There's still only about 1/8" clearance on the sides.
* Don't attach the header flanges until AFTER you get the spring hangers bolted where the two pipes widen to go to the cat back flange. If you bolt up the header flanges first, you will not be able to push the midsection high enough to get the spring bolt in (ask me how I know).

Hope some of this helps out the next guy.

I'll post results as soon as I can get back on the dyno (hopefully this week).

 

Thanks for sharing your learnings....

 

Sorry I'm seeing this late,we prefer you use our gaskets but if your stockers look fine they can be re-used. When I installed mine I forgot to take gaskets and re-used my stockers. Bell when you dyno let us know how you do Good Luck