Wow, how time flies. Not only is it once again time for another Throwback Thursday, but this is the last one for 2020. Let’s do everything we can to make this a great day. The arrival of the day after Hump day means another week is almost over. For this week’s look back, I thought we would take a short trip back to the beginning of this year to an article published in January 2020. Yes, I’m only going back a few months, but the information is highly relevant.

When we first published, The Iron Dome: Iron Cylinder Heads’ Relevance In The 21st Century, we mentioned how this topic of cylinder-head alloy came about from a question asked wanting to know why iron heads are still being manufactured. These days it’s commonplace to see different manufacturers offer aluminum cylinder heads ranging from as-cast to full CNC-ported at reasonable prices. Even billet-aluminum heads are becoming common. Cast-iron heads really don’t get the advertisement they used to.

The goal of the conversation was to find the attributes of both types of cylinder heads and where each is best suited. The goal was not to make a blanket statement and say one is better than the other, but rather, understand critical differences of each that will help decide which heads you should use for your engine build. We spoke with the cast-iron experts at World Products to get some technical info on the cast-iron heads it has produced for what seems like forever.

The valve guide and seat areas in a cast-iron head are significantly stronger and more durable than an aluminum cylinder head. In high valve-spring-pressure applications, this additional strength can mean extended time between refreshing, and a longer overall service life of the cylinder head.

In the original article, World’s Bob McDonald relays that the most obvious difference that enthusiasts notice is the weight difference. “Yes, cast-iron heads weigh substantially more than an aluminum counterpart. This is one of the major factors that consumers look at when choosing cylinder heads. Yet, for most street applications, weight is not going to be a factor.”

He also talks about some of the benefits that cast-iron heads offer over aluminum. “While the cast-iron head may weigh more, it does offer the benefits of additional strength and durability compared to aluminum. This is the most prominent attribute of a cast-iron head. By being durable, the cast-iron cylinder head can take abuse that would damage — or even destroy — an aluminum head.”

One of the benefits of a cast-iron cylinder head is that the deck itself is more rigid than a similarly designed aluminum cylinder head. That deck strength can be beneficial when used in grueling applications with forces trying to distort the deck.

There is a lot more interesting and what might seem surprising information in the original article, and to learn more, you really need to check out The Iron Dome: Iron Cylinder Heads’ Relevance In The 21st Century. Check back with us often, as we’ll be sure to bring you more great tech you can use.