What header gaskets?

SkidZ · May 11, 2010

The car is an '88 Corvette, L98 with stock aluminum heads.

I'm getting ready to install a set of Exotic Muscle headers and I'm not sure which gaskets (size/shape) to get. I've pretty much decided that I want to use these: Percy's Seal-4-Good aluminum.

http://www.percyshp.com/store/seal-4-go ... tml?page=0

I'm not sure which size/shape. Are the square 1.5" the proper ones?

grumpyvette · May 12, 2010

http://www.summitracing.com/parts/SUM-111405/

those aluminum gaskets should work ok, but Ive usually used copper as its far less likely to deteriorate
obviously your going to want to verify the heads exhaust port size and gasket alignment ,during the mock -up and install process, to make sure theres no significant restriction to port flow, and youll want to verify the header flange seals against the gasket
this is very common on some heads and the brand of header , its gasket flange design and the type of exhaust gasket used effects your results, paper or paper with metalic foil composite gaskets tend to burn thru if not 100% evenly clamped, as the least leak allows burn thru,copper header gaskets and use of proper bolts on the header flange tends to help, anti seize on the threads helps

on aluminum head's its almost alway's best to use studs to secure headers when you can,
as a stud has the threads full length engaged and very low stress , and significantly more surface area spreading the load,
than a bolt will ever allow,don,t forget too use anti-seize on the stud threads
shop around, the cost of the studs are not as high if you shop carefully, try a local bolt supply or hardware store.
http://garage.grumpysperformance.com/index.php?threads/header-gaskets.1045/page-2#post-55418
https://www.jegs.com/p/ARP/ARP-Exhaust-Header-Studs/744890/10002/-1

I would strongly suggest BOTH stainless bolts studs and the use of ANTI SEIZE on the threads

http://www.summitracing.com/parts/MRG-3409/?rtype=10

http://www.summitracing.com/parts/SUM-111405/

MR GASKET MAKES RECESSED HEAD HEADER BOLTS MANY GUYS PREFER

READ THESE LINKS
viewtopic.php?f=56&t=4541&p=12105&hilit=header+gaskets#p12105

viewtopic.php?f=56&t=1045&p=5159&hilit=header+gaskets#p5159

damn near anything works , for a header gasket at least for awhile, if the header flange is fairly flat and parallel to the cylinder heads exhaust port surface and you use fasteners that RETAIN a firm consistent clamp force, the problem most guys fail to recognize is that the repeated heat and cool cycling, tends to allow most header flanges to warp and bolts to slowly work their way out ward in the threads, once either condition or both happen the gasket clamp force varies and the gaskets leak.
design factors like thicker 3/8' and 1/2" header flanges. 14 and 12 ga tubes vs thinner 18 and 20 ga tubes ceramic coatings that slow heat loss rate all tend to reduce heat warping and the tendency for metal to expand and contract rapidly, which tends to aggravate the threaded fasteners backing out of the cylinder heads threads that hold the header flange problem.
If your gasket gets loose, you can try re-tightening the clamping bolts

and if the gaskets surface has not been damaged that should work, but if the gaskets damaged it will need to be replaced, thats one reason the soft copper gaskets are rather favored,

https://www.northwestfastener.com/d...ket-cap-screw-alloy-steel-1-hole-s-plain.html

because they are hard to damage,
obviously locking the fasteners,with a fool proof locking system, once they are correctly tightened in place to clamp the gaskets firmly, so they can.t come loose is a smart precaution

using safety wire pliers