Well, not really. There are a number of generally more and less generally academic boy's schools and I can't think of any that particularly specialise in sciences or arts.
The obvious gang mostly require registration in UK year 5 (turning 10 between 1st sept to end of August ) or 6 with preselection generally happening the following year, (ie year 6 or 7), mostly using computerised tests as the first sift which can often be done from abroad (see ISEB website, pretests). Prescreening usually involves English maths verbal reasoning and non verbal reasoning, then interviews (some, like Winchester, do things a little differently).
UK based children have to take common entrance or scholarship exams in year 8 but most schools offer a slimmed down set of exams for foreign-educated children , generally covering maths, English, science and often french if studied - you would have to check school by school. One boring factor for foreign based applicants is that having secured a conditional place in year 6 or 7 you would often have to pay a much higher deposit to hold the place (around a term's fees compared to £1k ish for UK based applicants ).
If he is boarding from abroad you need somewhere that offers full boarding and doesn't empty at weekends - you will see much discussion of this on Mumsnet. This knocks out Westminster which would otherwise be on your list for academics. You should also think about whether you want him doing A Levels (more common, but has them studying just 3-4 subjects for their last two years) or International Baccalaureate which, with 6 subjects, some people think is better aligned with a return to the states for university, if that is what you have in mind.
Re traditional boys' school, you should be aware that a number of the traditional gang have gone coeducational so you should probably spread your review wider than boys only, at least at first.
Remember to think about connections to airports.
Start by looking at Eton, Harrow, Winchester, Tonbridge for boys only and perhaps wellington college (offers IB) Marlborough, Sevenoaks (IB only I think), Brighton, Rugby, Kings Canterbury for coed. That would give you a good spread of types and styles but all good academically (look at a level and gcse league tables for comparison of outcomes, remembering that these schools are all to various degrees selective) and you can work out from there. Get a subscription to the good schools guide and trawl the websites to get a short list to visit when he is in year 5.