As long as you have the block sonic tested to check the thickness of the cylinder walls boring out that far is fine. I had an old inline six Jeep a while back that I bored out to fit stock Chevy pistons which is .150 over. Now I did use the best internals I could find, top of the line racing oil, a 160 tstat, dual electric fans, and an oil cooler to make sure, but when you're investing all that time anyways, why not.
So it is definately possible and safe if you have a block that can take it. Now is that going to be the best road for him, I don't know, maybe not, that's why I said it was his preferance. It really all comes down to what you can do, what you want to spend and just how much you want to push it and see what an enigine is capable of. I was just trying to let him know that he has ALOT of options.
Now don't get me wrong a 400 block would be a great start, I'm not saying your wrong just that it can be done. .
I like to push it, you know.
But that's just me.