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Header Gasket Leak
Have Hooker Comp Headers on Stang. Had to replace blown gasket on drivers side now pass. side starting to leak. My son advise ne to double gaskets for thicker gasket to correct any uneven surface between header and head. Any feed back guys?

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Alan L
Yes. If you have hooker headers (and you do) use the hooker gaskets. Solved my problem. Standard header gaskets didn't work, the shape was just a little off.

Get yourself some 'Stage 8' header locking bolts. A PITA to install but it will keep your bolts from backing out.

Install headers with gaskets, disconnect from tail pipes, fire it up, let it warm up, tighten bolts, then put on the special stage 8 locking things. Problem solved.

73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
I have always used copper gaskets on my headers and never had a leak or blow out. They are pretty thick and are a soft metal so they seal up well. And they are reuseable. I have had mine off several times and reused the gaskets. I tighten them done let motor heat up then tighten again and havent had any come loose. I just use stainless header bolts.


1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

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+3 on installing top quality gasket i would use a hooker gasket made for the header you have. +3 on warming engine up letting it cool back down and re-torque the bolts. they also make copper gasket spray for high heat and it works very well. you just spray it on the gasket allow it to tack up in the air then install. its added protection when you use a non copper header gasket.
I like Permatex ultra copper fo high heat areas.

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

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+1 on correct gaskets from Hooker. I've had the same issue with Hooker Boss 302 headers. You might consider a thin coat of black RTV, let completely cure, heat cycle, retighten. It works well for me

They key with header gaskets, is to maintain them. If you drive it regularly, then every 3-4 months, pop the hood and give them all a 1/4 -1/2 turn or whatever it takes.
If you keep on them, they should never leak.
I have always ran headers on my daily driver Mustangs, and have never had a header gasket blow out. Just need to stay on them.
Also, different from the other guys suggestions(with all respect), I have never used any permatex or high temp sealent on headers. Just the header gaskets from the manufacture and as I said, have not had any issues with gaskets blowing out.

The Hooker Super Comps don't match up well with the Fel Pro "steel blue" gaskets too well. There is a big miss match on the flanges VS gaskets.
I saw some gaskets at SEMA a few years ago made by PERCY that were a funky looking "scotch bright like" material.
With this design the gaskets would conform perfectly to the exh port.
I am still running the Fel Pro's but pulled them off and noticed a big miss match/leaks on the ports.
Yes I agree with running the Hooker gaskets and the Copper ones too. All good ideas.

Percy's 66052 - Percy's ''Dead Soft'' Header Gaskets

Percy's #760-66052
$32.99 Ships Today

These are the ones I was talking about:
XX Carbon Gaskets are designed to give the performance you expect at a price you can afford. They are made of Percy's proprietary 100% carbon material that withstands long-term exposure to over 2000º F, which makes for a lasting gasket! XX Carbon Gaskets offer superior sealing even on the worst flange surfaces, and they're ideal for nitrous and blower motors.

Percy's 68052 - Percy's XX Carbon Header and Collector Gaskets
Most people buy gaskets that conform to the header irregularities, but the best solution is to correct the irregularities in the first place. Simply filing the flanges flat before installation solves this problem 95% of the time. Then you can use the cheapest gaskets and they will still go the distance. I have the Hooker Super Comp headers on my Mach 1 on there for thirteen years now with no blowouts or retorquing. Even pulled the heads once about twelve yeas ago and reused the gaskets.

A simple solution to a common problem. It only takes about 10-15 minutes per header. Once you start filing, the imperfections will become very apparent. File them until they are smooth from end to end.

Black 1985 GT
Yellow 1973 Mustang Mach 1
Black 2012 5.0 GT, 6-speed, Brembo brakes, 3.73's
Wimbledon White 1966 F-100 Shortbed Styleside, 390ci, Tremec 3550, FiTech EFI
droptop73;63903 Wrote:I like Permatex ultra copper fo high heat areas.


73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.
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