Mustang 5.0 Header Gaskets - Ford Mustang Forum

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post #1 of 3 (permalink) Old 09-22-2013 Thread Starter
custom600rr's Avatar
Joined: Jun 2012
Location: Westminster
Posts: 128
Mustang 5.0 Header Gaskets

I'm sure this has been asked before. What is the best header gasket to use? I've read the old posts and they say Percy's in 2007. Just wondering if currently there is a better one or if that's still the one to get. Also does anyone know the percy's part number for 93 cobra heads? They have 2 versions. I'll buy the best so I don't have another blow out. All the bolts on head and collector are tight and I'm almost positive it's the gasket. Resorting to driving my Chevy truck until it's resolved. Bummed because the mustang is my daily driver.

1990 Ford Mustang LX coupe 5.0 conversion, 306 w/ 93 Cobra Heads, E303 and Explorer Intake, T5Z, aluminum driveshaft, 3.55 gears, tubular k-member with coilovers and a lot more.
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post #2 of 3 (permalink) Old 09-22-2013
cindys_sn95's Avatar
Joined: Nov 2007
Location: Gulfport
Posts: 7,170
PLANE OLD MR. GASKET PAPER GASKETS! the key is to re-torque 1 or 2 times after a couple of heat cycles. I have never had a header gasket leak.

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post #3 of 3 (permalink) Old 09-22-2013
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Joined: Apr 2009
Location: Miami
Posts: 13,094
Felpros are also fine. Like Marky said retorque and sometimes you gotta check them and retorque is necessary.

If they were fine for a while and then you developed a leak then you gotta check them every once and a while.

If not then maybe the flange area is not flat.

If the bolts keep getting undone then you have these header bolt gnomes that come at night and loosen the bolts to mess with you.

Also they have locking bolts like Stage 8 bolts.

2014 V6 Deep Impact Blue Mustang, Borla Type S, 2.73 (Uughh need 3.73)
1989 Sonic Blue Mustang LX Coupe, 349 ci,
392 rwhp 424 rwtq....Mustang Dyno
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