Header gaskets
Thread Starter
Instructor
Joined: Dec 2011
Posts: 197
Likes: 27
From: New Jersey
Header gaskets
I have a question. I just installed hooker headers and side pipes on my stock 1980/350 and of course the headers leak. I’m also using stage8 manifold bolts. I was wondering if anybody knows of a better gasket than what comes with the headers.
I’m still amazed how the stock manifolds had no gaskets and they didn’t leak!!
Thanks
Thanks
Le Mans Master
Joined: Oct 2007
Posts: 7,451
Likes: 974
From: RI, Now Franklin/Nashville TN
I always double up the gaskets on each side. I buy 2 sets of Felpro header gaskets, put red permatex between the 2 gaskets, clamp them and let them sit for a few hours to cure as one. Install. I have used this method on 3 sets of different headers, two of which the single gaskets would not seal completely and after the double gasket, have had no leaks for years now. I always use double gaskets now even on new headers like I put on my C3 1 year ago. Cheap insurance against leaks..............
Edit-I used Percys on a shorty header that was warped over time from the heat and it would NOT seal or solve the problem. The Felpro double gaskets did and now about 8 years on they are still on the engine on that car and not leaking.
Edit-I used Percys on a shorty header that was warped over time from the heat and it would NOT seal or solve the problem. The Felpro double gaskets did and now about 8 years on they are still on the engine on that car and not leaking.
Last edited by jb78L-82; Jan 20, 2018 at 08:13 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
The sealing flange on some headers is anything but a flat surface sometimes. Nicks, scrapes, poor weld flashing and warpage. An old trick was to take a hacksaw blade and score the backside (towards the head) of the flange between the front cylinder exhaust port and the middle port. Then repeat between the middle and rear ports. DO NOT cut very deep. Just enough to allow the flange to flex some.
As far as gaskets, had excellent luck with Percys header gaskets. Soft aluminum layers seal very well because they conform to all the imperfections of the flange. I believe there are seven layers of aluminum per gasket. Around $35 at Summit. And you can use them over & over again.
Another tip is to start the two end bolts, slip gasket in, then install center bolts torquing all bolts from the center outwards.
As far as gaskets, had excellent luck with Percys header gaskets. Soft aluminum layers seal very well because they conform to all the imperfections of the flange. I believe there are seven layers of aluminum per gasket. Around $35 at Summit. And you can use them over & over again.
Another tip is to start the two end bolts, slip gasket in, then install center bolts torquing all bolts from the center outwards.
Last edited by HeadsU.P.; Jan 20, 2018 at 07:51 PM.
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
I use SCE copper gaskets with my Hookers. Last time I removed the headers I could see soot tracks on the gaskets which tells me they were leaking a little, but until I saw that I couldn't tell they were leaking. At least that's better than any other gasket I have tried.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Retorque three times a year with boxend wrench, just for peace of mind.
Last edited by HeadsU.P.; Jan 20, 2018 at 08:01 PM.
Drifting
Joined: Mar 2011
Posts: 1,347
Likes: 121
From: Kernersville NC
I replaced mine recently with a Cometic gasket. I got it at O'Reilly. They have a black rubber like rough texture coating. I was not sure how well they would seal but they seem to work very well. I will have the headers off again soon and I will use them again.
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
Three times a year? I probably retorque them three times a month! Part of the problem I have is the bolts are very hard to get at, and some of them I can only get on with an open end wrench. I have the 3/8" bolts with the 7/16" heads but its still hard to get on a few of them. I have thought about looking for bolts with Allen heads but haven't actually tried that yet.
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Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Three times a year? I probably retorque them three times a month! Part of the problem I have is the bolts are very hard to get at, and some of them I can only get on with an open end wrench. I have the 3/8" bolts with the 7/16" heads but its still hard to get on a few of them. I have thought about looking for bolts with Allen heads but haven't actually tried that yet.
Last edited by HeadsU.P.; Jan 20, 2018 at 09:43 PM.
Le Mans Master
Joined: Oct 2007
Posts: 7,451
Likes: 974
From: RI, Now Franklin/Nashville TN
Another thing that I discovered about the grade 8 bolts with the lock washers which are a royal pain to get on. I had them with one of the sets of shorty headers that warped and necessitated the double gasket trick from trying different gaskets until the double gasket trick solved the issue. I decided to try using the grade 8 bolts without the locking washers since I was taking the headers on an off so often with the trial and error method to solve the warpage leak. Surprise! that after 2 heat cylces of tightening the grade 8 bolts without the locking washers, the bolts stayed tight and I have not had to tighten them in years. Regular header bolts require tightening a few times every season on my other cars...............
Last edited by jb78L-82; Jan 21, 2018 at 09:24 AM.
Melting Slicks
Joined: Sep 2016
Posts: 3,004
Likes: 104
From: NC
I hope you checked them for flatness before installing.
The copper or aluminum gaskets that crush are the best, having headers since the 80's I've used just about every header gasket and never used a double.
The ARP header bolts are about the best optiong. I've used locking bolts of various types and the issue is usually can't fit half the damn locking parts between bolt and header.
The copper or aluminum gaskets that crush are the best, having headers since the 80's I've used just about every header gasket and never used a double.
The ARP header bolts are about the best optiong. I've used locking bolts of various types and the issue is usually can't fit half the damn locking parts between bolt and header.
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
I hope you checked them for flatness before installing.
The copper or aluminum gaskets that crush are the best, having headers since the 80's I've used just about every header gasket and never used a double.
The ARP header bolts are about the best optiong. I've used locking bolts of various types and the issue is usually can't fit half the damn locking parts between bolt and header.
The copper or aluminum gaskets that crush are the best, having headers since the 80's I've used just about every header gasket and never used a double.
The ARP header bolts are about the best optiong. I've used locking bolts of various types and the issue is usually can't fit half the damn locking parts between bolt and header.
I've looked at most of the locking systems for header bolts over the years but I can barely get a wrench on my bolts. ( I have the stainless ARP's.) Pretty sure there's no way I'd get all that hardware in there. Best option I've found is the copper gaskets and retorque regularly.
Le Mans Master
Joined: Oct 2007
Posts: 7,451
Likes: 974
From: RI, Now Franklin/Nashville TN
I hope you checked them for flatness before installing.
The copper or aluminum gaskets that crush are the best, having headers since the 80's I've used just about every header gasket and never used a double.
The ARP header bolts are about the best optiong. I've used locking bolts of various types and the issue is usually can't fit half the damn locking parts between bolt and header.
The copper or aluminum gaskets that crush are the best, having headers since the 80's I've used just about every header gasket and never used a double.
The ARP header bolts are about the best optiong. I've used locking bolts of various types and the issue is usually can't fit half the damn locking parts between bolt and header.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Some guys use anti-seize, some use LockTite on the bolts. But the main thing is to check on them once in a while. I have never (knock on wood) had a header bolt loosen.
Le Mans Master
Joined: Oct 2007
Posts: 7,451
Likes: 974
From: RI, Now Franklin/Nashville TN
Apparently the grade 8 stainless bolts stay tight with no locktite on my bolts...I was and still am pretty amazed years later now (and I have checked them) that they remain tight......
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
I use the FelPro 1444 gaskets, anti-seize (alum. heads), and 3/8" head arp bolts. Check the bolts frequently as they will loosen with the heat cycles. I tried the stage 8 bolts but couldn't get the retainers on without grinding them. Useless with my headers. My .02.