Header Bolts Vs. Studs

So which do you prefer and why. I'm looking at a set of header bolts that will not back out but I'm hearing that bolts have a tendency to snap. Should I stick with studs?

there are some variables

Technically speaking studs are stronger than bolts. That is why they use them in race applications. When you torque them to spec you do not twist the entire length of the bolt, so when it is all said and done they hold better. Can reach farther in the block holding the tolerance better. They also don’t tend to snap inside the block because the major force is on the outside not the inside. If the stud is not bottomed out at the top or the bore they do not snap.


BUT a very big but

After you have properly installed the stud, IT IS a pain in the ASS to get all those holes to line up when installing headers, heads, and the like. The more studs the bigger the problem. This is a big issue if you are trying to install a manifold that is in the car and has an exhaust plumed to the manifold.

Studs and bolt all snap especially when dealing with the seasoning that an exhaust creates. And after you initially break the rust…with a stud,. You now take a chance of snapping the stud as you try to get the nut past that nasty, rusty stud( if the stud is bottomed out). They all suck. When dealing with an old engine I just cut of the bolt/stud, remove the manifold, and the remaining piece usually unscrews with your fingers.

Lucky for me the engine will be out when I do this. My issue is that it will not be very accessible when it's all put together and back in the car. I'm just not looking forward to retightening the studs after a few heat cycles.

if using good quality studs or bolts with good gaskets it is never a problem with re-torquing

Depending on the car, I prefer bolts simply because studs require a deceptively large amount of room to get the headers off. It might not seem like much, but many cars don't have the room to slide the headers straight out 1" to get them off the studs. Its not a big issue out of the car, but the first time you get a gasket leak you might be kicking yourself.

Depending on the car, I prefer bolts simply because studs require a deceptively large amount of room to get the headers off. It might not seem like much, but many cars don't have the room to slide the headers straight out 1" to get them off the studs. Its not a big issue out of the car, but the first time you get a gasket leak you might be kicking yourself.

That's the issue right there. It's an I4 and the only way to get off the header would be to remove the head.

For reference, here's the bolts I'm talking about:

http://www.summitracing.com/parts/PHP-20100

I haven't used those Percy's bolts, but I've heard great things about them. Go for it.