Sheered head bolt

Trying to take the head off, first two bolts came off with some encouragement, but the third has managed to sheer most of the head of the torq head bolt clean off leaving a nub that you can't really get purchase on. Tried another bolt and it has started doing the same thing.

Anyone has this before? Is there a special torx socket that gets on the head of the bolt better? And how have people resolved this in the past?

Gutted as I was making such good progress as the strip down.

drill it off

Yes Sir!!

Ended up having to drill 5 of the f*****s out! Does anyone know of an aftermarket upgrade that will avoid this issue in the future? I guess i dont ever plan on taking the head back off.

I always tap the socket on there a few times and lean on them now. Never used uprated items so cant answer the second question. I'm old school so would pop to a fasteners shop and ask for something of the same size/strength if I was in need. I'm sure you could get some arp bolts though

I think you have been pretty unlucky. I use a bluepoint socket which goes fully on and few taps with a hammer like @Adey. My dci head bolts were tight as fcuk and all came out.

Arp do a stud and nut kit but its expensive and not really necessary on stock 172. Id just purchase a decent snap on, bluepoint or similar high quality etorx socket and use oem or good aftermarket head bolts.