whatswithumans,

Some cylinder head design work that has already occurred for the 230/250 engines:

DOHC 4 Valve Heads
Project started by Primatech Motorsports, using 2 cylinder heads from the Chevrolet 3.4 liter V6 DOHC 24V engine, not produced
http://www.highperformancepontiac.com/features/hppp_0606_pontiac_sprint_six_engine_build/index.html


SOHC 2 Valve Head
Pontiac 230 & 250's 1966 - 69
http://www.classicaldrives.com/50226711/pontiac_ohc_straightsix_finally_gets_some_respect.php
http://firstgenfirebird.org/FAQ/engine/OHC.html
http://www.webrodder.com/article.php?AID=360&SID=4&CID=15
http://sohcsix.yuku.com/