Most of you will recall that the 3-1/2 litre Formula 1 of 1989 onwards saw the introduction of 5-valve engines for the first time: Yamaha V8 (Zakspeed), Ferrari V12 and Tickford heads for the Judd V8 (Lotus). These were followed a year or two later by the Yamaha V12 which was used by Brabham, Tyrrell and Jordan, in succession.
The only one which had some success was the Ferrari, particularly in the first two years, although Yamaha did use five-valve designs on their production superbikes for a number of years. If memory serves, they won a few World SBK races too.
On the Yamaha superbike engines, the three inlet valves were arranged along the arc of a circle, concentric with the bore, hence not along a straight line. Thus the centre one of the three valves had to have its stem angled slightly so that it could also be operated by the same camshaft. Otherwise three camshafts might have been needed.
I am looking to understand how the F1 engines addressed this same issue, and would be grateful if anyone can post cutaway drawings, or pictures with the cam covers removed, of any of these engines.