A friend of mine is putting together a street/strip engine to run in the foot brake class. It's a 355 ci chevy engine using a new cast crank(2 piece), shotpeened reconditioned X rods with arp bolts, speedpro hyper. flattop pistons and hastings moly rings. All has been balanced with a bob weight of 1924.2. In your opinion, how hard can this assembly be turned safely with out mass destruction? He seems to think 6800 rpms. I think more like 6500 max.

In my opinion, with used stock rods (I don't care if they are pink, X, PM, whatever) and a cast crank I would limit RPMS to a max of 6500, although I would shift at 6000 to see how the powerband was...

Mike,
The main thing here is the weight of the pistons. The 355 in my Camaro I raced for years had stock 5.7 rods with Pioneer bolts and I shifted it at 7500 rpms but ... I had a set of ultra light weight Manley pistons and a steel crank.
I would stick to 6500 rpms if he wants it to live. We have several circle track engines that run stock rods and run 6500 rpm all day. 6800 is probably pushing it if he wants it to live a long life.