Learn the Evolution of NASCAR Engines from a Man Who Was There

Stock car racing is a bit of a misnomer these days, given how far the race cars have diverged from the vehicles you’ll find on your local Toyota, Chevrolet, or Ford lot. That said, following the thread of how a race series evolved is often fascinating. The powerplants under the hood of NASCAR stockers have evolved significantly over the years, even if a casual observer will still label them all “small-blocks.” Exactly how different are they from factory engines? Well, a lot.

The story of how stock-car racing evolved into very-not-stock-car racing includes more than just left turns. Some changes have been incremental, others massive. That is true for nearly each and every part of the cars, and the powerplant has been one of the most controlled areas. Regulations and rules are tightest around the engine, because it is likely the easiest place to get creative—often, the sanctioning body has no way of inspecting the powerplant until after the race, and by then, an inspector has to consider the effect of wear. After a race, what was illegal may only be questionable.

Different strategies of cheating get a lot of chatter, but a lot of those stories look like fish tales as time goes on. Rather than focus on the things that may or may not have happened, YouTube channel Stapleton42 visited Automotive Specialists, a shop with five decades of experience building NASCAR-spec engines, owned by the legendary Keith Dorton.

According to Dorton, in the early days of stock car racing, engines did at least start with original equipment parts from production vehicles. It wasn’t long before those parts were being modified and beefed up to support the abuse that racing puts on them. For example, the teams would take an engine with a two-bolt main cap and replace it with a four-bolt cap that had splayed studs. The swap reinforced both the block and the cap and kept the rotating assembly stable at higher rpm.

The next evolution was what has become known as the “Bowtie” engines. These involved cast-iron heads, which required a lot of porting to get to the power level racers desired and, when finished, were very delicate. So delicate, in fact, that Dorton states multiple teams were using a ceramic sealer in the cooling system to try and minimize cracks and damage over the course of a race. It’s rare for someone with first-hand experience in the engine room to talk so candidly about the development of and the differences between racing engines, and it’s one of the things that makes this video such a treat.

As the NASCAR series grew and the rulebook became tighter, engines like the SB2 and R07 have come out of the woodwork. If you dig deep into those, you’ll learn some really amazing things about how to build durable and powerful engines. Dorton even mentions that when helping with a land-speed racing engine program, the base they chose was the SB2 NASCAR engine, because it was built not for low-end punch but for high-rpm power, which is what a land-speed car needs.

Even if you are only a casual NASCAR fan, consider giving this video some of your time. The way Dorton walks around the shop, picks up the actual parts, and discusses them is really cool. Even better, the host is very knowledgeable, so the questions and conversation are great. I feel like I now know the basics of how to build a NASCAR engine, and I am also smart enough to know this really in-depth half-hour still didn’t even scratch the surface.

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