Being a wedge (closed chamber, quench, parallel valves inclined at a small angle to the bore axis, just like the 1949 Cadillac and Oldsmobile) isn't the problem.
The LS makes the common observation that "engines are more successful as they approach hemi design" a far stretch - the hemi is, by the away, many decades older, Harley-Davidson since 1926. The iron Sportster and Chrysler 392 are remarkably similar (both 1957) and both to WW1 aircraft engines.
Kaase remarked years ago that the correct intake valve was the biggest one you could fit, and the exhaust valve gets whatever room is left.
"All big blocks have inadequate valve area" (Vizard).