The valves sit pretty offset on the chambers but I found it hard to imagine
48mm inlet valves in a 79mm A15 bore but I guess with some nothing its possible
but thats almost 6mm larger than a 42mm inlet valve which has been fitted to an A.
Yet at 9800rpm Im sure the 16v or even Ga16i 3 valves chambers put out more hp
as the 3 valve head runs finger followers the 4v are direct cam actuation but
maybe the 8v heads have nice torque band or 16v is not allowed.