Not sure on standard rods being good for 300+ , might be wrong though! Thought standard rods with arp bolts are good for 260-280bhp anymore and you idealy need steel items? Ive had H section rods put in mine for peace of mind and I was told I needed them to go for 300+! If you need any help give area six a call hes more than willing to give advice and im sure thers not many people that know more than him in this field?!