This N/A 10,000-Plus-RPM Small-Block Ford Makes 3 Horsepower/Cube

Whenever we talk about EFI University having their hands in a project, you know there’s going to be something that spins to the moon. After all, Ben Strader is the High Priest of High RPM. However, this particular project is outside of what normally comes out of the EFI U shop, for a number of reasons.

First, it’s a Ford. Not that the team has anything against small-block Ford engines, but until this project, they really weren’t the platform of choice. Secondly, EFI U is usually working on the own R&D or teaching projects, no so much on customer projects. And third, while he has experience in some of the top levels of heads-up racing, Strader’s projects aren’t usually aimed at a power number, while being constrained by a rulebook.

However, when NMCA N/A 10.5 racer Robbie Blankenship approached him last year for some help, Strader decided to branch out and team up with Blankenship. “Robbie originally came to me because he was interested in trying to learn the value of EFI vs carburetors,” explains Strader. “At the time, he was only running carbs and wanted to know more about EFI. He actually showed up at one of my Fuel Injection classes that I did in Florida. Through that class, he got to learn a little more about me and my personality and the way that I think.”

That class not only sold Blankenship on the idea of converting his high-winding 400-inch combination to EFI but also sold him on Strader himself. “He called me a few weeks after the class, and we got to talking about his engine, and he got around to asking if I’d be willing to help with the EFI conversion,” says Strader.

“Somewhere along the way, during those conversations, he said he thought he was going to change engine builders. He threw out the idea of me building his engines, and it caught me off-guard because, at that point, I didn’t even have any kind of model to have an engine customer, we’d only done our in-house stuff. It went from helping with the EFI conversion to ‘Can you help straighten out the valvetrain?’ to ‘Can you just build the whole engine?’ That’s how we started the project.”

Optimizing the valvetrain was more about adding durability than power. The amount of longevity the team has gotten out of the combinations so far is almost unheard of at this level of racing.

Diving Right Into The Engine

The original goal for Blankenship’s project was to simply increase the reliability and longevity of his race engines. “Part of his reliability issue was that he was constantly chasing the carburetor tuneup so that he wasn’t burning up the pistons and rings,” explains Strader of Blankenship’s original desire to switch to EFI.

“The other part of Robbie’s issue was having to constantly deal with the valvespring and valvetrain-related issues that were hurting his ability to go rounds and win races. [His struggles] were never a function of how much power he had, but rather being able to live through multiple rounds of racing.” The fact that it wasn’t a clean-sheet redesign meant there would be some challenges ahead, having to work with certain parts that might not be what Strader would have chosen if starting from a clean sheet.

The billet Winberg crank is fully polished and has profiled counterweights, to help minimize windage inside the engine.

The basis upon which the entire engine is built is an iron Dart “file” block. A file core block is essentially a tall-deck block, which has been sectioned in order to reduce deck height, but without heavily machining the deck of the block itself. “You end up with a short deck block, but all your water pump holes and the depth of the head bolt holes, and water jackets are all in the right location as opposed to just decking the snot out of a tall deck block,” explains Strader.

However, the file block is something Strader would probably eliminate if starting from scratch. “As the deck gets taller the distance between the ports gets farther apart. To keep the short runners, and still ‘connect the dots’ your plenum has to get larger,” explains Strader.

The Dart block is a file core, which has had the deck height shortened, but with all of the components in the proper locations.

“A larger plenum can hurt your vacuum signal which negatively impacts your carburetors. With the switch to EFI, we don’t care about the pressure signal to the boosters anymore. So I am firmly of the opinion that deck height doesn’t matter nearly as much as it used to, and I’d probably just use a standard tall-deck block if we were to start from scratch.”

That block has been bored heavily to 4.205 inches. A 3.610-inch stroke Winberg billet crankshaft spins freely in Clevite bearings. As would be expected in a naturally aspirated engine of this caliber, a set of billet aluminum rods from MGP are bolted onto the crank. Hanging off the end of those rods is a set of Gibtech custom billet aluminum gas-ported pistons.

A set of incredibly thin Total Seal Diamond Finish piston rings measuring .020 inch-thick on the top ring, and .023 inch for the second ring, are paired with a comparatively massive 2mm oil ring. The sealing of those rings is assisted by a billet aluminum Dailey Engineering six-stage dry-sump oiling system.

As you can see, the Gibtec billet pistons are vertically gas-ported, and have an incredibly small .020 inch, .023 inch, 2mm ring package. The MGP aluminum rod is standard fare for a naturally aspirated engine of this caliber.

Optimizing The Top End

Moving up top, the cylinder heads are a set of Ford Performance raised-port, canted-valve D3 castings, which have been worked over by Slawko Racing Heads. While the D3 heads are carryovers from the previous administration, everything else is new, as part of the valvetrain optimization program undertaken at EFI U.

Starting with the camshaft, which is a Comp Cams 63mm tool steel “clamshell” journal design, there was significant work to the lobe profiles to maintain power and optimize the system’s stability. Surprisingly, Strader had no problem sharing most of the lobe specs with us. It uses a split duration, with 276 degrees at .050-inch lift on the intake side, and 303 degrees at .050 inch on the exhaust. The lobes of the camshaft have more lift than the average SBF camshaft has at the valve, with lobes measuring .580 inch intake and .565 inch exhaust. All that is combined with a 119-degree lobe separation angle.

The Jesel .927-inch keyed lifters ride in the bronze bushed lifter bores. These are fairly standard high-end parts, but don't venture into the land of exotic.

A Jesel belt-drive system keeps the camshaft in precise timing with the crankshaft. Riding on those large cam lobes is a set of equally large Jesel .937-inch diameter keyway-guided solid roller lifters. A set of Trend Performance 1/2-inch diameter, .200-inch wall, bronze-tipped pushrods ride on top of the Jesel lifters and translate their motion to a set of Jesel Pro-Series steel shaft rocker arms, with a 1.85:1 ratio on the intake rocker arms and 1.75:1 ratio on the exhausts.

Those rocker arms actuate a set of Victory 1 titanium valves on both the intake and exhaust sides of the chamber. Controlling those valves is a set of PSI dual valvesprings which are designed for up to one inch of valve lift. They provide 445 pounds of pressure on the seat, and north of 1,200 pounds of open pressure. While it was typical for these types of combinations to need new valvesprings after as little as a few runs, Strader has been able to get much, much more lifespan out of them now.

The previous aluminum rockers (left) next to the new Jesel Pro-Series steel rocker arms. They measure in at 1.85:1 on the intake and 1.77:1 on the exhaust.

“We are changing valvesprings between races now, as good practice, but I don’t know that we have any real data justifying that we need to be changing them that often,” says Strader. “By the time we were done testing on the Spintron, we had made something like 36 runs above 10,000 rpm on the same valvesprings, and then put 20 runs on them on the dyno before we changed them for the engine’s first trip to the racetrack.”

We’d be remiss if we didn’t focus on the combination’s new induction system. After all, it was what originally led to Blankenship and Strader meeting and working together. The star of the show is Holley’s Terminator X Dual 4500 EFI system, Strader worked closely with Holley on the system’s development, and between the massive airflow capabilities (Holley advertises 1,440cfm per 4500 throttle body) and eight 100 lb/hr fuel injectors per throttle body, the system combines all the benefits of EFI with the benefits provided by carburetors in this application.

This is the HRE billet and sheetmetal intake manifold. You can see that the plenum is a traditional sheet metal design, while the runners and intake flanges are machined from billet aluminum.

The two throttle bodies in the kit are mounted atop an HRE billet and sheetmetal intake manifold designed specifically for this application. The Holley Terminator X ECU controls both the spark as well as the flow of VP Racing Q16 race fuel. The whole combination is capable of spinning to at least 10,600 rpm, and makes “around 3 horsepower per cubic inch.” Obviously, in the world of heads-up drag racing, you don’t give away all of your information, but you can do the math, as well as run the numbers on Blankenship’s quarter-mile passes and get an idea of the power the engine is making.

The EFI University Treatment

“[Robbie] was willing to give up some power in search of reliability, and fortunately, we were able to give him that reliability without giving up any power,” says Strader. But that reliability didn’t just magically appear after swapping in a few parts. The first step to optimizing the combination was to identify what was actually there.

One of the huge advantages is EFI University’s in-house Spintron. Access to these awesome machines is fairly limited, so having one readily available (as well as knowing how to interpret the data) has been incredibly helpful to Blankenship’s effort.

“I didn’t want to just disassemble it, clean everything up, and put it back together again,” says Strader. “We spent the better part of a week blueprinting the engine and ended up with 16 or 17 pages of data from all the different measurements of the engine. And then we sat down and talked. I said, ‘Here’s what you have.’ And he was blown away. He’d never had anyone supply him with that much data about his engine before. I think that helped develop a deeper trust between us. That led him to ask what I’d do differently. So I basically listed all the reliability changes I’d make in various parts of the engine.”

Once the duo identified areas that could use improvement, it was time to start testing ideas and validating parts on the Spintron. “Hands down, having the Spintron is the difference between what we ended up with as an end product,” says Strader. “Because there aren’t that many Spintrons available and the cost of going to a major race team or manufacturer to try and use one is prohibitive, I think the fact that we have that in our corner was a monster level of advantage for us.”

Being able to test out different parts and combinations without risking damage to the engine, whether you’re looking for power or reliability, really lets an engine builder push boundaries. “The things we were able to do and try, and the confidence it gave us to not only go to the dyno with a new combination, but to show up to the racetrack with it is unmatched,” Strader explains.

“If you’re only building engines with “known good” parts, you’re never going to be on the leading edge that way. You really have to be able to try new parts and shapes and stuff. I’ll put it this way. I think anyone can make as much power as we make, that’s not magical. But, I don’t know that you could do that AND have the reliability we have. I don’t want to develop a system that will meet our design goals, I want a system that will exceed the goals, and do it many more times than we expect to need to do it.”

Here you can see the gorgeous Dailey Engineering dry sump pan with its integrated six-stage pump.

Good Enough, Isn’t

With the ability to test and validate almost any wild idea they come up with, the issue of “good enough” takes on an entirely new meaning. “It’s really hard sometimes to accept ‘good enough’,” Strader admits. “I’m always looking for that last 20 horsepower. The logical side is going, ‘This 80-percent is better than the other guy’s 100-percent,’ but I always struggle with how much is enough. We have a saying around here that good enough isn’t good enough, but at some point, we have to say, we have to stop here otherwise we’re never going to move the entire project forward.”

That struggle shined through when the subject of the engine’s displacement came up. Blankenship has been running the 400 cubic-inch combination for a while now, even though the N/A 10.5 rule book has a huge number of potential weight breaks, some of which Strader thought might be slightly more advantageous on paper.

The Holley Terminator X 4500 system flows 1,440cfm and has eight 100 lb/hr injectors per throttle body, so multiply that by two, and that’s what feeds Blankenship’s engine.

“I think there’s a sweet spot in the rulebook that is probably somewhere between 380 inches and 420 inches, based on what the weight breaks are, and my opinion that this is a horsepower per cube class,” says Strader. “The bigger the engine, the more total power you can make, but the less power-per-cubic-inch you can make. From a practical standpoint, I inherited these engines at 400 inches, and I didn’t see enough justification to do a whole new rotating assembly to try and change that when the money could be better spent optimizing the rest of the 400-inch combo.”

However, Strader does feel that he would make some changes if he were working from a clean sheet of paper. “If we were starting from scratch, we would very much be evaluating whether we wanted to be on the higher or lower end of that 380-420 cubic-inch range,” says Strader. “I would probably gravitate towards the lower end of the scale, and turn more RPM, because I feel there are some advantages there, but someone else might think the risk and costs that come with higher RPM aren’t worth it and gravitate to the larger engine sizes. 400 is a nice compromise — right in the middle.”

With all of the improvements made to Blankenship’s engine program, having a backup engine is almost not needed. However, as Strader pointed out, minute differences in two engines that are “the same” mean both engines get the same Spintron and dyno testing and validation.

Theory is good and all, but we don’t race Spintrons and dynos. In the first two outings with the car, not only did Blankenship find himself in the winner’s circle, but he did so with record-eclipsing elapsed times, posting a best of a 7.761-second pass. Then, in this year’s racing, Blankenship has further dropped that to a 7.694, which is only .022 from the current (at the time of publication) class record.

“I attribute a lot of the success to the fact that all of the people on Robbie’s team, and Robbie himself, all click so well together,” says Strader. “Racers, in general, tend to be emotionally driven, but I think as an entire group we tend to be extremely data-driven and unemotional. We all made a pact to check the egos at the door, and only look at the facts and the data and make the changes that make sense.”

Power aside, the engine’s reliability has been vastly improved as well. “We have half of last season — so three races — on it and the plan was originally to bring the backup engine up to snuff, and get it to him before the beginning of this season so that we could start with a fresh engine, but delays have caused us to continue to run the original one,” Strader explains, with there currently being five events — almost a full season — on the primary engine.

This is Blankenship’s primary engine, which dipped below the class record e.t. at the end of last season. Still running strong this season with no refresh, it’s gone even quicker.

“I jokingly said to him, ‘Be ready, we’ll be running this engine at Indy [the last race of the season],’ and I’m not so sure that’s not achievable, although that isn’t really the goal,” Strader laughs. “Keep in mind, he was rarely able to finish a single race without refreshing something on the engine, and now we’re at five races in. I tend to believe there’s between 60 and 80 full quarter-mile passes on his combination before we really have to be serious about opening it up.”

Blankenship’s engine program is proof that the Spinal Tap project was much more than just a parlor trick, as some critics have contended. “We learned a lot from Spinal Tap that we were able to apply to projects like this, but Spinal Tap was so different, and everything was focused very differently, since the goals for the two projects were nowhere near each other,” Strader explains.

It’s clear to see that whether he’s working on an R&D challenge or a real-world competition optimization, Strader is proving that EFI University can walk the walk, and more than hold its own in one of the most competitive naturally aspirated classes around. The out-of-the-gate performance is proof that both the methods of validation as well as what he teaches students in class is more than just fancy book learnin’.

 

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About the author

Greg Acosta

Greg has spent fifteen 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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