My reading indicates cast iron heads may be superior for performance, IF flow
numbers are the same, and some real world factors like hardened valve seats for
unleaded gas are included, higher octane gas, the cast iron may be superior to
aluminum heads.? The recent explosion of available aluminum heads with newer
designs, typically out flow stock vintage cast iron heads, and the included
hardened valve seats are a bonus.? The cost of port and polish and adding
hardened valve seats to cast iron heads, combined with some weight savings, and
maybe the possibility of running a little more compression without race gas
seems to make aluminum heads an easy and cost effective solution. The after
market is probably swamped with aluminum heads do to a lower cost to design,
manufacture and machine compared to cast iron.? One caveat on Tigers, many
aluminum heads are dimensionally different than OEM castings, making firewall
clearance and header/ exhaust interface a concern.? Some aluminum heads utilize
stock dimensions and exhaust port locations, some alter these dimensions.? Some
headers offer different size tubes, that may align better with the exhaust
ports on non stock heads.
Randie
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