When it comes to V8 performance, General Motors has stuck by the pushrod engine. The iconic small-block V8 engine lives on to this day and shows no signs of coming to an end in the near future. But, pushrods are pretty outdated compared to dual-overhead camshaft setups. What’s so great about them?
Engineering Explained tackled five reasons why pushrod engines still exist, and their benefits check off a lot of boxes. The first is low-end torque. Pushrod engines have a habit of making lots of torque down low in the rpm range. It’s due to airflow and the fact pushrod engines normally use two valves per cylinder. This is also the reason pushrod engines don’t rev incredibly high.
The second is a relatively simple design. Unlike DOHC engines, pushrod engines are not complex in construction. In the engineering world, if a solution can be achieved with a simpler design, it just makes sense. Pushrod engines feature a single camshaft in close distance to the crankshaft, which means a belt, gear or chain doesn’t have to travel far to rotate the camshaft.
The simple design moves into the third and fourth advantages: size and weight. A pushrod engine’s overall packaging is much smaller and compact than a DOHC engine. Pushrod engines are also shorter, which allows engineers to place the engine further back in the engine bay to work on center of gravity.
Finally, cost. The video cites an interview with GM’s chief engineer for small block engines where the automaker said its pushrod V8 is about $400 cheaper than a DOHC design. Multiply $400 by hundreds of thousands of engines, and the cost benefit is clear.