My opinion he's probably better off listening to his builder than randoms on the internet, but I would think about switching to 400 block instead, bigger bore, 20 more Cid or run a 3.915" for same ish cid 470 but the 383 will still perform well enough if that's the choice for whatever reason.
To me depends on your rpm goals, where do you want hp to peak where do you want it to shift ?