I have hooker 2055 headers/y-pipe on my '88 GTA. I have had problems with leaks with these headers since I put them in my car. I've replaced the gaskets, and made sure I torqued the bolts down evenly from inside to out, and retightened them etc etc and I still have leaks!!! It doesn't help either that this POS is a real pain to work on, especially when you're trying to tighten down the header bolts on the passenger side.
Anyway, a friend of mine recommended that I that cut the flange in each area between adjacent ports. He said it will allow each port to expand independently from the rest of the header when it heats up, and it will keep the bolts from loosening up on me. It makes sense but I'm a little hesitant to start cutting up a set of $350 headers, not to mention more wasted time. Now this guy had a lot of experience building circle track cars and engines, so I assume he knows his *hit. What do you guys think? Has anyone ever tried this?

*The attached rendering of the header flange shows exactly what I'm talking about. The red lines would be where I'd cut the flange.

 

alot of headers come like that, and for this exact reason. first it cant hurt anything, and second, it makes it to where they can move independently closer to the head with out the flange holding it back.

 

Yea, it can't hurt to try it. Alot of headers come cut like that. What I'd do before that though, is take the header off and put a machinists straight edge accross the flange, and see how straight it is. If its more than 1/8" off, then cutting the flange might help you.

 

This would really suck because they are on your car, but you could remove them and bolt them to an old head off the car with no gasket. Use a feeler gauge set to see how much gap there is and where located. If it's too large and cutting flange doesn't solve the problem you might have to take a trip to the machine shop and have the flange sanded flat. I had this problem with 2 different sets of SLP's (which come with separate flanges) and had to have them machined flat to fix leaks.

 

Try Earl's graphite insert gaskets, work like charm.

 

I have those Earls gaskets they are great. No more gasket blowouts. Definatly a nice product and worth getting.

 

Use Napa Nitro Seal gaskets. If you cut those flanges the headers will WARP. If you look at the SLP headers that come without a full flange, the FLANGE is like 3/8"+ thick. Considerably bigger than the hookers anyway. I've NEVER had a problem with my hedmans (Smaller flange than both).

The SLP headers I've worked on, once they warped, it's an absolute bear to get the bolts in because the pipes have spread away from the center section.

 

SLP’s are notorious for that. I’ve seen multiple sets for sale cheap because they had warped flanges.

FWIW, cutting the flanges like that may allow the bolts to pull them flat (especially if they have reasonably long tubes), but you may also end up with the SLP problem, that they fit great the first time around but after you get a few heat cycles in them if you take them off then never want to go back on flat (this is more of a problem stainless headers with stainless flanges. A good fix for it is to use mild steel flanges on stainless headers).

If it was me the first thing I would do is pull them off and see where they don’t seal (it will be obvious, you’ll have plenty of soot in that area, usually the 2 center ports also), and then figure out why (lay a straight edge across it and you’ll find high and low spots) and then use a file or belt sander or something similar to flatten the flange (it doesn’t have to be super precise, I think most machine shops would just slap it on a belt sander).

Or, if you’re lazy (like me), you can usually get away with adding some of those grafoil individual port gaskets at the port that is leaking. My headman’s were leaking at the center 2 ports on the driver’s side and I didn’t feel like pulling them so I got one of those grafoil gaskets, loosened the bolts and dropped it in there with the gasket that was already in there. It worked fine for like 10 years…

 

Mike says . You've never kept a car on the road for that long, unless it lasted 10 years because it sat (like under a big tree, like from a hurricane)!!

 

my headmans kept leaking at the center ports burned a set of gaskets every week,the last set of gaskets I bought I soaked them in soapy water for a hour or so till the swelled up then let them dry then installed havent leaked since (2 months)

 

I'll get flamed for this, but I've had really good luck with Mr. Gasket Ultra Seal header gaskets. Last several years when standard gaskets last less than a year usually.

 

Figured that while everyone was offering tips on header gaskets, i'de join in. I took a little tip from the LS1 guys who are using stock manifold gaskets on headers. While our cars do not com with manifold gaskets, stock 98 vortec 350 truck gaskets work great. haven't had a problem with mine.

 

I've pulled the headers off probably three times by now. When I pulled them off, I checked to see if the flange was flat and that the ports were relatively in line with each other, and they seemed fine. How "flat" should the flange be? Is there some runout limit or something like that? BTW I also tried the trick with soaking the header gasket in water already and it still didn't work. When I first got the headers, I bought the expensive Percy's aluminum header gaskets, and they didn't work too well.

 

i would definitly try a set of $40 gaskets before i put my $400 headers under the knife...

-chillen

 

i'm running the percy's "dead soft" aluminum gaskets on a set of hedman longtubes, which are notorious for having warped flanges. no problems whatsoever. i am very pleased. i was turned on to the flange gaskets after i installed a set of their collector gaskets and they didn't blow out. i've met some of the guys that work for Percy's and let me tell ya, they are some stand up guys!

 

I've heard that the thin gaskets used for cast iron manifolds actually work really well with headers.

 

I've been using copper gaskets with the 1 3/4 SLP's for the pass 6 years and reused them and never had a problem. Some of you people run your engines temps above 220 degrees often.

 

Those earl's are nice and work awesome, but they can be a pain to put on. Those graphite inserts can fall out and even break easily if you're not really careful installing them. Notice they also don't have the slotted end boltholes like many conventional gaskets. You may want to try the deadsoft aluminum ones or copper ones first, if that doesn't work... do the earl's. Or just go straight to the earls.