Oh God

[nando]

75 is not much. I'm sure it's safe to reuse the head bolts. I'm sure the final torque is higher then the 75 you put them at. I'm not really even sure they are TTY bolts. Subaru engines call for degree torque specs but the bolts are not really TTY. They use the degree torque method to compensate for creep. Creep is when the bolt head tries sticking to the aluminum surface and makes that loud clicking sound. That sticking will give a higher then true torque reading before breaking loose. This may or may not be the safe case with BMW.

Its not a POS Subaru, and they are TTY.

Theres probably a way to figure angle from the torque you put into them, but a set of bolts is only $25. I'd replace them and do it correctly. I'm guessing 75ft/lbs isn'tactually enough to reach the yield point on the bolts, but there's no way to know how much further you need to turn them

Also, you dont want to bring them up to full torque in the first pass, so even if you did know how much further to turn them you should still replace them all and start over.