Do I need ARP head bolts for a 50trim upgrade.

[john]

As stated before, you do not need them but you should get them. On my 6 bolt with a 50 trim, I ran stock head bolts and had no problem at 22psi. I blew my HG later at 18 psi and threw in the ARPs and a stock HG with out copperspray. I have not had any related problems since. You can do it now when you have time or later when you blow your HG. If it were me, I would do it now as you are pulling the cams off anyway.