Opening A Time Capsule — Dynoing A 1990s NASCAR Engine in 2022

We have espoused how far we’ve come as an industry, technologically speaking, time and time again here on EngineLabs. However, it’s not often we get to see apples-to-apples comparisons of old technology and new and especially not in the context of a NASCAR Engine.

No one will argue that NASCAR Cup engines are some of the most technologically advanced V8 engines of their time, whether it be 1992 or 2022. Technologies developed for use in competition, constrained by a rulebook, often find their way into the performance aftermarket — albeit several years after they win races for the NASCAR teams.

Enter the Speed family. Lake Speed has had a long history of successes in racing, from karts to NASCAR, and then back to karts and vintage stock-car racing. His son, Lake Jr., has enjoyed significant success in his own right, and any fan of EngineLabs knows who Lake Speed, Jr. is. So when a recent YouTube tour of Lake Sr.’s shop uncovered a NASCAR engine from the ‘90s which had been sitting dormant for some 20-odd years, after Lake Sr. won some vintage stock car races with it.

90s NASCAR Engine

Once the bottom end was opened up, some really quality parts were found, like a Hank The Crank crankshaft and Carrillo connecting rods.

Since Lake Jr. shares many of our sensibilities, we see it as only natural that he had the idea to resurrect this 358 cubic-inch engine not only to its former glory, but elevate it to a level that would surpass its previous best thanks to the use of modern technology. “Dad bought this engine at an auction and then had one of his friends rebuild it for vintage racing,” says the junior Speed. “Rarely do you find an engine this old, that is still running. This is really a time capsule. I’ve got some numbers in my head of what I think is possible out of this engine.”

So, with his idea fully gelled into a plan, the first step was to pull the engine out of the shop and take it to a dyno.

Getting A Baseline

The first thing to do before tearing the engine down to figure out what, exactly, they had, was to hook it up to an engine dyno. For that, they headed out to a well-known NASCAR engine shop, Pro Motor Engines. Its owner, Dennis Borem, isn’t just a great engine builder, but is well-versed in this specific generation of stock-car engine.

“This [engine] is a snapshot of what Cup racing was 20 to 25 years ago,” says Speed, Jr. “This is probably an early-90s-spec engine that was refreshed in the early-2000s to be vintage road raced. It’s been sitting for about 20 years. It will be cool to see what this engine actually does. Then, take it apart, and keep the same head manifold and block, see what it can do.”

NASCAR engine dyno

No matter what the team tried, they couldn’t get the engine to make the power they thought it should make.

The only thing known for certain by looking at the engine from the outside is that it’s a C3-headed combination with an 820cfm double pumper carburetor sitting on top of an SVO intake manifold. With the engine on the dyno, and Speed Sr. thinking it made north of 700 horsepower when he parked it two decades ago, expectations for the engine were pretty high.

“It was totally common for a Cup engine to be down 10 or 15 horsepower at the end of a race,” explains Speed Jr., drawing on his experience on a championship NASCAR engine team. “This one has four or five races on it. So if it was down 50, I wouldn’t be that surprised. Plus, it’s just been sitting for a long time.”

It’s got a lot of blow–by. — Dennis Suderko, Pro Motor Engines

After a couple of minutes of run time to make sure all was good, Pro Motor Engine’s dyno operator, Dennis Suderko jammed the handle forward and zinged the engine to 8,000 rpm. Again, and again, and again. However, the numbers weren’t coming back as anything anyone in the room expected.

“It’s got a decent amount of torque, it’s just falling off up top,” says Suderko. “It’s done at 8,000 rpm.” The team tried adding timing, reducing timing, and messing with the carb and were rewarded with… nothing. Nothing they tried seemed to change the number. 480 horsepower. Over and over again.

The Ford C3 head, while not the latest and greatest, is still a stout performer. Between a new valve job, and all new valvetrain components, there will be quite a bit of power recovered here. Plus, with some additional compression, these heads should perform to their potential.

Digging Into The Issue

With lots of initial hopes dashed — the engine was down 150 horsepower from where even the most conservative guesses were — it was time to figure out why. “We really have no idea what is inside of that engine,” says Speed Jr. “We’re gonna find out and that’s the fun part. We have a mystery to solve now.”

Initial theories were that the rings were just absolutely shot. After all, it sat for 20 years and was showing about 7 cfm of blow-by during the run. But, quick to dash that thought was the fact that it still showed 170 psi in compression checks. Another question was whether or not the engine was actually 358 cubic inches, as it acted like it was a smaller engine on the dyno.

Pro Motor Engines owner, Dennis Borem, even went so far as to check the camshaft profile to make sure it had the right cam in it.

“Blow-by didn’t fluctuate; it started high and stayed high,” says Speed Jr. “Vacuum was 6-7 inches and it stayed at 6-7 inches. It wasn’t responding to RPM in a way that would make you suspect there was a broken ring or something messed up and wrong. The fact that it didn’t respond to additional timing suggests that it might be lower compression as opposed to a smaller cubic-inch engine.”

As the teardown continued it was clear there were a lot of good parts used in the engine. Right off the bat, a period-correct high-end crankshaft from Hank The Crank was spotted, along with a solid set of Carrillo connecting rods. While the pistons were a quality set from CP Pistons, their design was aged, with a full-round, non-boxed design. Their diameter ruled out a lack of displacement, but it quickly became apparent that the pistons were the culprit.

And the problem reveals itself. Those are reverse-dome pistons, designed to bring compression down to 9:1. Not what the C3 heads want, and the root cause of not being able to break the 500 horsepower mark.

“These pistons were for a 9.0:1 compression class they had back in the day,” says Speed Jr. “They are dished. These heads were designed for high-compression with a big domed piston, and we have a piston that is less than flat.” Speed also guesses there is a significant amount of power loss in the C3 cylinder heads’ worn, outdated valve job.

He jokingly quips that the bar has been set really low for them, with the 480-horsepower dyno results, as back-of-napkin math shows there are a lot of gains to be had in this engine combination, and picking up a ton of power shouldn’t be impossible. Especially with several industry powerhouses already on board to supply modern parts and knowledge for the project, this should be quite the build.

Speed concludes this phase of the project with a quote from Robert Yates about a C3 NASCAR engine of the era, saying that 700 horsepower was enough to win a race. So the bar has officially been set for this 358-cube, C3-headed Ford engine. Can the team modernize the mill enough to pick up 220 horsepower? We’ll be following along to find out.

Testing the cylinder wall finish with a Mitutoyo profilometer showed what was a pretty standard hone finish for the era. With todays modern rings, Speed would like to see about double that Rvk.

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Greg Acosta

Greg has spent nineteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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