View Full Version : Stainless steel for exhaust manifold bolts

Dan White
07-24-2008, 07:04 AM
Although I typically avoid stainless steel bolts in load bearing applications due to them not being as strong as grade 8 , I was looking at the bolts on my exhaust manifold and thought they might work ok in this application and keep the rust down. Years ago I used brass nuts on SBC studs and that worked pretty well. I just don't want a situation where the bolt gets stuck and twisted off trying to get it out. Anyone tried using stainless in this application?

Dan White
64 R1 GT
64 R2 GT

Chucks Stude
07-24-2008, 08:05 AM
I remember rebuilding a Stude engine that had all stainess exhaust bolts, and two regular. Had to drill out the regular ones. Do not ever remember having a broken stainless bolt.

07-24-2008, 09:12 AM

I'm using stainless steel for all non load bearing engine fasteners (e.g. pretty much everything external to the engine save for the head bolts.) No problems so far. Use anti-seize with any stainless fasteners; they don't rust, but they can gall, the anti-seize will prevent this and keep everything happy and free.

Somewhere on my HDD at home I have a spreadsheet that I whipped together from some parts book research to allow one to generate a pick list of stainless fasteners to buy to dress up one's engine.


55 Commander Starlight

07-24-2008, 09:37 AM
Ditto on Nate's advise. I always use Never-Seize on any bolts/studs on the exhaust system. Always use brass nuts on the exhaust manifold pipe flange studs. If they strip when removed, toss them, run the appropriate die down the stud, install new brass nuts, you're good to go.;) It's when people take a short cut and install a steel nut instead of a brass one, that's when the stud breaks resulting in a PITA.[xx(]:(:(. Hope this helps.:)

Dan Miller
Auburn, GA

Road Racers turn left AND right.

07-24-2008, 10:46 AM
As with everything mechanical, there are varying grades of stainless steel fasteners. The bigboximport non-graded stainless is often softer than an OEM steel fastener. I wouldn't use the import hardware for the exhaust. If you can get an appropriate grade of stainless fastener, then it will be OK.

Of note, no fastener will seal a corroded, uneven exhaust manifold or head surface. After many years of po'boy fixes, I've learned to have the shop doing the heads either mill the head and exhaust manifold flanges or if not too bad, sand them flat and shiny on their 6'x 2' belt surfacer. Makes all the difference.

thnx, jack vines


07-24-2008, 05:06 PM
There are grade 8 stainless bolts, but most stainless hardware is not
much better than a grade 2 bolt. Stainless steel rusts too. Better
off just using good quality OEM hardware - of course thats coming from
someone that lives in California.;)


'63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: TKO 5-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires

07-24-2008, 05:38 PM
Studebaker tried it. Stainless bolts came on a lot of the 232
v/8's. I don't know about other engines.

Tex E. Grier