340 to 372 stroker kit
Build what you want... He's got a good block to build on. I went to look at a 340 when I bought my project motor only to have it be a 360.
Still bought it because it had lots of good parts and was repairable.
Big HP needs a big bore like a 340 can provide. That said he surly won't be lacking power. I got my *** beat several times by a 340 50 years ago...