360 build info needed,,

Don't bore it any more than it takes to clean it up. The more you bore it the thinner the cylinder walls get and that lets them flex and you loose ring seal. That'll cost you way more hp than you'd ever get from boring it out bigger.

RHS heads are a huge improvement on old worn out original J or X heads and probably cheaper too cause most J heads you find are worn out and need totally rebuilt. They were good for their time but as with everything time and miles take it's toll on parts. BTW: you only need small valves for 350 hp with either head you use.

For 350 hp. you don't need a huge radical cam. I have a Lunati 60404 in my 360 and it's making about 375 hp and it's much more mellow idling (although it thumps decent) than a Mopar perf. 284/484. Really you don't even need one that big for 350 hp. I'd bet the Lunati 60403 or Comp XE 268 would make 350 easy and be very streetable. You might even get some resemblance of fuel mileage. An Eddy RPM or Air-gap would go a long way toward making 350 hp also as would a set of headers. A 650 carb tuned properly will make 350 hp.