I think the general rule is 600hp, A few years back we built a 416 w5 engine out of a 70 340 and broke a cyl wall 659hp @ 7k, We rebuilt on a 74 360 block with 414 cid using the same top end and cam but went to alu rods, lighter pistons and steel 2 bolt main caps with studs... turned that combo to the high 7ks with no problems for the first year.. Ended up caming down for high 6ks for the last 2 years with no problems so far, But I don't know exactly how much power the newer combo makes.... I call it @ 599hp to play it safe