Senior Tech Team
Join Date: Dec 2004
Location: Belle Plaine, MN
Re: Cast Iron vs Aluminum Cylinder Heads
The theory was that iron heads would hold more heat in the chamber, while the aluminum heads would shed that heat into the cooling system more readily than the iron.
That all makes sense, but all the new chamber research shows up in aluminum heads first nowadays, so a more efficient chamber in an aluminum head more than makes up for any potential heat loss over an iron head with a lesser chamber design.
Personally, I'm a huge fan of internal engine coatings. I get the best aluminum heads I can, and then coat the chambers, valves, ports, and piston tops with ceramic engine coatings. This insulates the chambers/ports and keeps more of the heat in the chamber.
Because of the coatings and the weight savings, not to mention the ease of repairs, I'll never run an iron head again. It's like the roller cam thing- yes, they're more expensive, but I'll never run a flat tappet again either. Too many advantages to rollers...and aluminum heads, for that matter.