I am installing the exhaust manifold back on the engine. 77 302. Can I or should I reuse the old bolts? I see autozone has a new set for 30.00 and some other place has a set for 100.00. Not sure the difference. Or can I get grade 8 bolts and install them with lock washers? thanks

 

I put stainless steel bolts in all my exhaust with antiseeze. Have not broke any since. They are usually just 5/16 or 3/8 bolt threads depending on the engine.

 

You can use the grade 8 bolts too with the lock washers. Use antiseeze on the threads.

 

If they are not buggered up I see no reason not to re-use them. If replaced, probably best to go with dedicated manifold bolts. They likely have an alloy designed to handle heat better than standard fasteners. Grade 8 is strong but maybe not made for that application.

 

Chase (use a tap to clean) the holes, and get new bolts. Yes on grade 8 from a place like Fastenall and get some Nord lock washers from them too. And yes anti-siez for sure. Torque to specks and pattern IAW the manual, hot torque and a cold tq ck.

 

Thanks everyone. I did see the originals have a special washer with "teeth" that grab.


I will look into the norlock washers now.

 

Waste of money to go with stainless. And not really designed for that application. Even with anti-seize it can gald up in a cast iron head. And when you use anti-seize,try to get some of the hi temp type. Good for (I think)up to 1800 degrees.

 

Nord-Lock are 2 separate washers with teeth that face each other when installed and torqued, never loosen up.


Nord-Lock wedge-locking washers | Secure your critical bolted joints with the original lock washer from the bolting experts


Sears, Northwest tool, Fastenall, I always use them on my exhaust manifolds. And look into Remflex exhaust manifold gaskets or the ones JBG sale. Both are very good and no chance of an early burn out.


Make sure that the mating surfaces of the head, exhaust manifold and your hands are oil and grease free when installing them. Any contaminate to the gasket can cause a burn out.