https://www.enginela...aign=EL 4/30/25
t’s no secret that here at EngineLabs, we love naturally aspirated engines. Nitrous is cool, and boost is awesome, but at the end of the day, being able to make big horsepower numbers with nothing more than the atmosphere the Earth gives you is the sign of a great engine build. So, when we saw this 429 cubic-inch, 351 Windsor-based engine built by ZSR Engines, making 2.1 horsepower per cubic inch on pump gas, pop up on our Facebook feed, we had to know more about it.
Zach Smith, the founder of ZSR Engines, decided to specialize in Blue Oval powerplants when he hung his shingle out in 2015. “I worked in shops that did all makes, but I was always more knowledgeable about the Fords,” Smith explains. The decision to focus on Fords was more than just based on passion and knowledge. By specializing in one make, he felt it would actually expand his reach, instead of just being the local engine shop. Specialized customers allow him to focus on what he enjoys, as well as streamline the shop’s operations.....
A Killer Cleveland Top End......In order to make killer power naturally aspirated, you need a set of killer cylinder heads. Without the ability to force air into the cylinders, having a perfect port design that will move air at atmospheric pressure is absolutely crucial. In order to accomplish his goals, Smith looked down under, turning to Higgins Race Heads in Australia.
Smith opted for a pair of Higgins’ 3.3 Cleveland heads. The “3.3” in the name denotes the 3.3-inch minimum cross-sectional area of the intake port. On these heads, the intake port flows a whopping 411 cfm at .900 inch of lift, while the exhaust port flows the 255 cfm at the same lift. This is thanks in large part to the Victory 1 2.230-inch titanium intake valves and the 1.600-inch titanium exhaust valves.....
