Can these torx headed bolts be replace with strong hex head bolts. I hate torx bolts, I had to crack them loose with vice grips cause I broke two bits.

 

Sounds like your bits were weak, not the bolts. Yes you can replace them.

 

Keep in mind the cam gear may not clear the cam retainer bolts if you use something that doesn't fit quite the same. I'd stick with the same type of bolt... the extra mass of the hex head will most likely collide.. especially with a double roller.

 

I used hex head bolts on mine, but like Javier said, you have to make sure that nothing will make contact with them when your timing set is installed and turning.