Need help with Headbolts!

I recently got my hands on a 16vt coupe that is heavily modified and i started renovating the whole car with engine rebuild.
The threads in the block was modified to m12x1,5 from m10.
My question is anybody know what bolt can i use from another car? The bolt that was installed has Male hex head 16mm and it is 180 mm long and i cant find it.
I found a bmw 320d bolt that has the dimensions i just need to cut it to size, but im afraid it will strip the threads from the block, because of the high torque setting.
Can anyone help who has experience please?

Thanks!

I have no connection with this so don't know the quality, but you do have - https://deltaparts1.wordpress.com/deltaparts-shop/engine-parts-modified-section-2/

Thanks!