I need to tighten my exhaust boltsat the head, what can I use to get to them? Sockets are too thick??

I've been able to use a 3/8" drive 13mm Craftsman socket on all 8 of them, with an extension.

Edit - make that a 12mm socket. I do have the correct copper exhaust stud nuts.

You must have a set of quality sockets, Craftman, Mac, Snap-on etc. They are stronger by haveing a larger outside diameter than the cheap ones.

I use a 1/4" drive 13 mm deep socket for mine.

have tried a 3/8 craftsmen deep socket?

Look for a cheap socket rather than something nicer like a craftsman or snap-on. The cheaper ones will most likely be thinner walled and allow you to get in there. Bring your socket to the store with you when you look for one to compare.

1/4 inch drive and extension will give you more wiggle room to get around the exhaust pipes.

The factory nut is a M8x1.25 nut that fits a 12MM socket. Standard, hardware store nuts use a 13mm wrench and can be a PITA to work with. Bug shops should have the correct, copper plated nuts.

I use a 12mm one of these in a 1/4" drive with a tee handle and 6" extension.
The socket OD is the same size as the nut flange.

what brand is it? Is it deep enough?

SNAP ON

The one in the picture is a Snap-on. (reference picture only)
The one I use is from Orchard Supply.
I think it's a Craftsman.

Wobble extension = worth its weight in gold.
I got mine from the Snap-On van
First click and your socket can pivot 10-30deg all around at the attachment point (tighter than the one above)
Second click and the socket is on the extension SOLID
This works for all sockets (mine is 3/8) and is handy for almost all weird angle, tough to reach nuts, including those exhaust stud nuts. I use mine all the time!!

Questions about depth relate to original configuration. My heads have several studs that are longer and require either a deep well socket (if I have the room) or a 12mm socket with the extension NOT clicked in, so there is room for the stud to protrude. Also, previous exhaust stud repairs often leave studs skewed. You can actually pry on the stud to get clearance for the socket, but I'm sure it weakens the stud's attachment to the head- but I have done that before (pry with screwdriver between exh pipe and stud in my case) and the stud stayed in.

I can't recommend against doing that enough. Breaking off an exhaust stud is not going to make you very happy person.

Just get a socket that will fit, it's not that hard. And be careful of over tightening them. Get a torque wrench and tighten to spec. (I think spec is 18 foot pounds, but some like myself go less than that.)