Superformance header...gasket or not?

[Woodz428]

Like many I use ultra high temp permatex and have never had a leak. Something that may avoid another leak, regardless of what route you take, is to re-check the header bolts periodically. The expansion and contractyion properties tend to cause the bolts to lose torque over time. I recheck mine at least oncfe a year while I check the other fasteners. I also use thread-lock on the bolts, whether that helps or not is uncertain. But after decades of running headers on many different cars, I find that the re-torqueing of the bolts is the best preventative exercise.
I have also ,over the years, found that running a file over the flange reduces irregularities that can promote leaks.
If using a permatex high temp sealant, it is best to snug the headers up and allow the sealant to cure prior to final torqueing. I believe that many times the curing process is overlooked and the headers are torqued up when installed, that doesn't allow the sealant to set and causes it to be "squished" thinner than it should be, creating the potential for leaking.

[madmaxx]

Fantastic info and Thanks!!!!! Mine is past 2700 so it appears I may have the "wrong" gaskets. My header flg has TWO SETS OF HOLES, does that tell me anything? There are 6 numbers with a backslash between them, kinda looks like a date, not easy to read.

Originally Posted by wanab5150

The 1415 gaskets are the correct size for the old Superformance headers that everyone used before (right). They are 1.48 tall and 1.25 wide....the "402" headers used mostly after car #2600 use the "402's" for ALL Roush motors and they are 1.62 tall and 1.42 wide fitting the Roush / AFR head.

The photos show both headers. When you look on the top of the flange near the firewall you should see"402" stamped into it, if not, type in "Superformance Exhaust" in the search thread. The old style small headers choke your exhaust about 30 % or better.

The 402's are on the left and a set of the old SPF headers on the right that have been used on a Roush 427. You can see the overlap. An angioplasty is not going to help in this case....The 1415 gaskets seem to be the same size as the old header shown on the right.

[vector1]

another thing with the one piece header flange, aluminum expands around 2x the amount of steel, so they are constantly working each other. if you can tolerate it split the flange between the pipes and use rtv or any gasket and it will work well. i split with rtv and no problems, rtv the bolts also holds them in. if you have the one piece flange, i would suggest a gasket that will have sliding properties like copper to hold together, but the two dissimiliar metals will work against each other, so maybe enlarging the header bolt holes will allow some movement.

[wanab5150]

Went up to Summit in Reno to pick up the #1487 Fel Pro gasket. Talking to them, it is very common to NOT run a gasket as many of you state. No one around here sold that particular gasket.

As Panavia states he uses the #1415's on small port headers and #1487 on the newer 402's. I matched the 1487's to an AFR 205cc head at Summit. I also matched the 1415 gasket to the small 185cc heads. The 1415's seem to be the gasket for stock size 351 ports and 185cc heads (not on Roush 427's).

One area of concern is between the port and the bolt hole. As shown in the photo, there is only about 1/8th inch of gasket space and part of it protrudes into the port to be burned off.

I'm ready with the gaskets but just want confirmation there's enough gasket coverage to seal and not blow out through the bolt hole .

Check out the photos of the two different size Superformance headers and my headers, ready to clean and install.... Is the gasket safe or not? Please......

[wanab5150]

Photo #1 is the one showing the minimal clearance................

[PANAVIA]

If you don't safety wire your header bolts , make sure they are coated with anti seize and put them on your pm schedule , along with checking brakes etc. Steve

[madmaxx]

Thanks wanab150!! I will have to order some in addition to verifing if I have the restricted headers or the new style. At this point I can only laugh at the commedy of errors I have experienced with this ownership experience.

As far as an 1/8" my guess it will last for a while. As PANAVIA suggest constant retorqueing will help prevent a leak. Bottom line you got a crappy job on the exhaust header fabrication and as you know the customer pays in the end.

[wanab5150]

Yes , I think it was an inaccurate build on the headers.

As far as the more restrictive headers, if you have the stock 2" mufflers then I don't think a switch is necessary, however, my Harley has 2" headers and mufflers and that's just for one cylinder.

I think if I had stock Superformance 2 inch mufflers and the older restrictive header I would leave it alone as the change to big headers and 3 inch exhaust only seemed to make a difference above 3500 rpm. It was fast enough before, but I already had the big header so I just cut out the 2" exhaust and added 3 inch "Chambered exhaust" mufflers. Plus, I really just wanted a heartier sound when I did the mufflers in the first place. Like I needed more power?????

Panavia...I bought those bolts with the little half moon and clip.....hope those will work. AND one last question....do you see an issue with the clearance ...would you still use a gasket with that? thanks

[maurice19]

Tom, You probably blew it out making those 11 sec. runs at the strip.
Maurice

[wanab5150]

Maurice...I still have 14,000 miles on the Roush warranty and I don't want them to know what doing with their baby...Shhhhhh!

[maurice19]

Roger that

[wanab5150]

Gasket on....we'll see if it lasts

Heading out to Snakes to the lake tomorrow with the other 42 Cobras from the BACC. Three days in Tahoe. Tour of the Thunderbird Lodge , drives, reception with tequila and snacks on Friday night, and
another tequila party on Saturday night after the day drive. My kind of party. This is their 14th year.

[wanab5150]

I did the gasket on the side that blew out. Also use a bolt with a little half moon shaped attachment that slips over the bolt and then clipped in place to keep it from rotating ( similar to safety wiring).

I went to change out the other side and I can only get one bolt out. I think George Atlas torqued these down, and Pee Wee Herman did the side that blew. There's no room for a box end and a barely room for a open end that will strip the head. I've tried running the motor for a minute to heat the head and get it before the bolt swells but that didn't work.

If you look at the above photos you will see what I mean.

Other than using a cutting torch, grinder, jack hammer, or similar tool , does anyone have suggestions how to get these little buggers out?

[pgermond]

I used a hole saw in the foot box to gain access to the rear bolts on my Big Block, and then made plugs that can be removed if needed to remove or tightened the bolts. Worked out pretty well.