Volume III, Issue 7, Page 14

But For an Accidental Incident...

In order to get the full impact of this story, we’ll need to re-wind the clock to sometime in 1971. Airflow benches hadn’t yet made an impact on the automotive aftermarket community and high-performance and racing product manufacturers had the luxury of simply filling in performance voids that the OEM didn’t have a willingness to explore.  So if you were a performance parts manufacturer (and chose not to copy your competition) and wanted to enhance engine performance, for example, you simply built on the design platform used for major engine components, in their stock configuration. Simply put, and as a general rule, bigger was better.

Applying this approach to aftermarket intake manifolds of the day, principally those for street performance applications, you simply played off the stock piece by making runner passages and plenum volumes larger… with the possible exception of separating the upper and lower planes of a V8-type design to draw air/fuel charges alternatively (in the firing order) from the upper plane to the lower one.  It was a 180-degree design because each plane was used repeatedly, every 180 degrees of crankshaft rotation, and frankly, some of these aftermarket manifolds were highly effective. Hold that thought.

I’d received a call from a friend of mine who claimed to have an intake manifold design that would “out-perform any 2x4 manifold capable of fitting under a stock hood.”  Because I was at Edelbrock and since I knew Vic and my friend didn’t, would I provide an introduction to see if the company wanted to build and sell the new design?  The three of us convened. Vic and I soon discovered that the “new design” was a partially-finished concept drawing that needed verification to validate the performance claim my friend was making.  However, it sparked Vic’s interest and I was given the responsibility of converting the line-drawing concept into a functional model we could test and, most importantly, compare to the best single 4V manifold in the Edelbrock line.  As it turned out, no small chore lay ahead of me.

At this point, there’s something else you need to know. We hand-built prototype intake manifolds out of fiberglass, based on proprietary methods we’d developed inside Edelbrock (a practice that lasted for decades in the R&D department).  And despite a notable number of dyno experiences with early versions of these ‘glass prototypes that included fire-associated implosions and explosions, we’d managed to make the construction process pretty fool-proof.  (You might opt for the “fool” part of that statement as the operative word.) 

Nevertheless, given particular care during engine cold starts (that still included random backfires into these somewhat delicate induction systems) that was the way we built a prototype. As a practical matter, the process was relatively quick and economical, especially when compared to temporary tooling and castings that could quickly consume a meager R&D budget.  Besides, with the ‘glass pieces, fire extinguishers proved way less expensive and testing was a lot more adventurous.

Interpreting the drawing as best we could, I built prototype #1. At the time, we reckoned this would be the only prototype so we didn’t number it anything until #2 came along. I should also mention another little piece of relative information.  All this is taking place in the spring and we’d intended to introduce the “new design” at the SEMA Show in October.  If that sheds little light on the situation, keep also in mind we’d planned to begin running “teaser” ads in the print media prior to the show and, if you’ve had any experience with print advertising you already know “lead times” for ad deadlines typically run two months ahead of publication release.  So if it appears that we were gearing up for a lively game of Russian roulette, you’re dead on.

Prototype #1 didn’t pass muster.  In fact, it fell below peak power of the then-current Edelbrock single 4V design by about 20hp.  Since the clock was running, we decided to bring my friend into the picture. Together, we built prototype #2, this time including all the magical features he’d said made his design unique.  No dice again.  However, as he and I continued our review of #2, we began to identify little nuances believed to hold the key to unlocking the design and fulfilling all his original proclamations.  So we worked through several modifications to #2 and still it didn’t draw blood.  The clock continued to tick and as it was running down, so was Vic’s patience… and “teaser” ad number one had already been released.  Armed with what we’d learned from protos #1 and #2, I built #3.

By now, I’d taken up virtual residency in the Edelbrock airflow room and the bench was running pretty much non-stop, weekends included.  My friend had essentially expended his idea list and I was running solo, resolved to find a solution, I frequently aligned and held the prototype up against the test cylinder head while the bench was running. Then late one Sunday afternoon, holding the manifold against the head and evaluating yet another change to the prototype, the manifold slipped… just slightly.  In the process, it became somewhat skewed to the port’s axis.  Instantly, the bench recorded a significant increase in flow.  I shut it down, re-positioned the manifold to its skewed position, flicked on the switch and the flow increase repeated.  In an instant, we had the answer, and all that remained was to verify the “accidental” discovery by constructing prototype #4… which we did, in a matter of days.  (Don’t forget the ads and Vic’s waning patience.)  Subsequent tests revealed this final version to be 20 or so hp better than the baseline Edelbrock production manifold. We released the design to tooling… along with one final teaser ad.

By now, among your other questions, one asks why this story has any particular relevance to the evolution of aftermarket high performance and racing intake manifolds.  Here are a couple of reasons why it might.

The manifold we’ve been discussing was the original Edelbrock, single-plane, 4V manifold named the Tarantula.  It quickly morphed into the Torker and then became the Scorpion; the former directed primarily to street applications and the latter to racing.  A special feature of the Scorpion was that the manifold was air-gapped, becoming the first single-plane, single 4V aftermarket manifold to physically separate runners from the engine’s oil galley.  It was already the first single-plane, high-performance and racing single 4V manifold in the automotive aftermarket.  Where racing rules allowed, it became the dominant, single 4V manifold in drag racing and NASCAR at the time and in less than two years. Competitors to Edelbrock copied the concept, lending their own spins to the basic premise of a plenum connecting all runners in a single plane. 

Experiences surrounding the piece are far too numerous to discuss here but included countless hours and a lasting friendship with Lingenfelter, sorting out ways the Rochester QJ could work on the design (originally intended for square-bore Holleys) and then with leading NASCAR and drag race engine builders wanting their own “filed core” (slightly illegal) versions. We even went up against a retired Zora Duntov when he was consulting for Holley and produced their version of a single-plane, small-block Chevy 4V design.  In retrospect, he enjoyed that as much as we did.

So when you glance at any of the current single-plane, 4V V8 manifolds today (independent of engine brand), you can now say you’ve been privy to the story about how the whole notion came about.  Fate has strange ways of laying down paths for even the most blind of us to follow.  And in this particular instance, had it not been for an accidental incident…  

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