bolts or studs for stock exhaust manifolds

[clintC]

rebuilt motor/new manifolds...are studs w/ lock nuts a better/suitable choice instead of having to cut a 1/4" off the bolts I picked up yesterday....if so, do I still use anti-seize or blue loctite on the stud to head & does the lock nut throw off the torque reading

 

[fast 99]

Didn't describe the engine, assume a small block. Never used studs from the factory, use what GM used unless you have aftermarket aluminum heads, then use what they recommend.

 

[Ricko1966]

rebuilt motor/new manifolds...are studs w/ lock nuts a better/suitable choice instead of having to cut a 1/4" off the bolts I picked up yesterday....if so, do I still use anti-seize or blue loctite on the stud to head & does the lock nut throw off the torque

Get the correct bolts and washers and yes they are odd lengths. if you use anti seize you will have to reduce your torque readings. Do not use split lock washers,they just lose their tension with heat. Personally I'd just tighten them using common sense,after first heat cycle check them, in a week check them eventually they will quit moving.

 

[Radiohead]

Get the correct bolts.

You'll appreciate this later on.

 

[Turbo4whl]

As stated, correct bolts. The best bolts IH used on their 345 engines. Years ago you could buy just the middle size for your GM. Copper coated steel, the IH set now five bolts, 3 sizes. Some sets are still available, way too much money.

You must be registered for see images attach

GM exhaust manifolds have 2 holes to locate the manifold. Studs will be trouble when you want to take the manifolds apart.

 

[fast 99]

Many used a thick small OD flat washer.

Really all I ever used if anything was a drop of oil on the threads.

Don't overthink it.

 

[clintC]

wasn't able to find a bolt set locally (just header bolts) for the stock application (3/8 16 2 1/4), that's why I grabbed some grade 5 (I read anything stronger weakens w/heat) 2 1/2's and planned on cutting down if the stud idea wasn't practical

 

[clintC]

Many used a thick small OD flat washer.

Really all I ever used if anything was a drop of oil on the threads.

Don't overthink it.

if I didn't overthink things.....what the heck would I do with all that unwasted time

 

[fast 99]

if I didn't overthink things.....what the heck would I do with all that unwasted time

LOL,

Reason I said that is sometimes people get into trouble trying to reinvent the wheel. Many times duplicating the factory is easier, less costly and more dependable.

GM knows GM products.

 

[75gmck25]

You may also need an exhaust manifold spreader if things don’t quite line up correctly. Cheap tool, but it can really help if holes in manifold don’t quite line up with the head. I got mine from NAPA.

https://www.amazon.com/dp/B0009OR94W/

 

[Turbo4whl]

You may also need an exhaust manifold spreader if things don’t quite line up correctly. Cheap tool, but it can really help if holes in manifold don’t quite line up with the head. I got mine from NAPA.

https://www.amazon.com/dp/B0009OR94W/

The OP did state new manifolds. Don't usually need the spreader unless they are old and a little warped.

 

[Ricko1966]

wasn't able to find a bolt set locally (just header bolts) for the stock application (3/8 16 2 1/4), that's why I grabbed some grade 5 (I read anything stronger weakens w/heat) 2 1/2's and planned on cutting down if the stud idea wasn't practical

O.E. bolts are bad enough about breaking after enough heat cycles. If you can't get the correct bolts,or arp bolts, I'd get grade 8s and grade 8 washers. I can just see 16 broken off grade 5 bolts next time you try take off the manifolds.