As it concerns to this post, really is worth build a 390 over 365, is spending $$$ for 25 cid over worth it especially getting a worse bore size along with a even poorer b/s/r ratio. I don't think it is, to me it 318 vs 360 vs 408.
Does that mean the OP can't build a killer 390 no but to me it makes the least sense.
Yep, it's what you have and what you want to build. Why do people build slants or 273's. Because they can. I likevthe idea of a 390. It's an underdog. Everybody builds 408's. 415's not as much because of availability.