They have a street 12 port head and a race 12 port head. Both have rather large valves and high flow characteristics which may require more cubic inch. I saw an ad in the Power Manual of one of their 12 port heads that said it was a 60 hp bolt on.


1966 C10 292/tko600 http://67-72chevytrucks.com/vboard/showthread.php?t=596643
1964 C20 292/sm420