As you look at this shot of a beautiful red on red '67 Corvette convertible sitting atop a rollback, you have to wonder what its story is. The wheels and tires are probably the first thing to get your attention, then your eye picks out the subtlety of other replacement bits like the seats, rockers, and the exhaust system that exits out the center of the rear panel, just before you reiterate the obvious that it's sitting on top of a rollback. As the story goes, the build is completed at this point and this project '67, which started life as a numbers-matching 350 horsepower convertible, is on its way to the dyno to have its new fuel-injected 425HP crate engine setup.
The GMPP ZZ383 has a proven combination of technology with its roller drivetrain, pump gas friendly requirements, and sheer performance with 425HP and 449 lb.-ft. of torque. These impressive performance figures are due in large part to the taller Vortec heads this engine comes with, with their larger intake ports and specific chamber design. The spec sheet states these figures are achieved with a high-rise aluminum intake manifold and a big Holley carburetor on top. Problem: We couldn't use a tall aluminum intake because it wouldn't fit under our stock small block hood, and we didn't want a carburetor anyway. So we began our research of fuel injection. We knew that we didn't want T.B.I., or any port injection that would require an air cleaner sitting on top of a throttle body on top of the intake manifold. Nothing against it, we just didn't want that look with this project. GM tuned port injection seemed to be the answer, but we had some reservations about how much a stock tuned port would flow. Remember, we have some killer heads on this engine, which leads us to another speed bump. A stock (normal) GM intake manifold, be it carbureted or injected, will actually bolt to these heads via their dual-bolt pattern design, but it won't cover the extra-large intake ports. Can you say massive vacuum leak? This led us to Accel, where they advertise a "special" tuned port setup called the Street Ram with oversized runners, a larger throttle body, higher flow rate injectors, and a manifold that fits the Vortec heads. The manifold was actually Edelbrock's High-Flow T.P.I. Vortec baseplate, but worked very nicely for this application, and is one of the few T.P.I. intakes for Vortec heads. And, dimensionally, it looked like it might even fit under the small block hood of a midyear Corvette.
We're glad you could join us for this final segment of the Reconsidering Your Line in the Sand series, where we have showcased the installation of today's advancements on several classic Corvettes, but mostly on this '67 convertible. The scope of this series has been to illustrate that you can have an NCRS hat and a SEMA hat hanging on the same rack in the corner of your garage. That is, you can satisfy two disciplines and do everything outlined in this series of articles without, as I've said all along, "burning any bridges." By this, I mean that after enjoying the fruits of today's advanced technology and improved comfort, your classic Corvette can be put back to stock to take its place on the judging field once again, should you ever wish to.
In this segment, I've been asked to answer some detail-oriented questions by a few folks as to how things worked, how they fit, whether they were compatible, what I would do differently, and so on. In other words, to get to the specifics of what I will call the peripherals of this project. It's one thing to write a short discourse on a given work, but our learnedness will benefit by knowing what happened behind the scenes, or "between the sentences". Jump in and take one more ride with me on this subject, but don't be surprised if we hit a bump or two.
It all starts with a plan, just like any project. The primary focus of the plan should be "Where you want to end up?" instead of "How are you going to get there?". The latter is something that needs to be engineered, modeled, tested, scrapped, re-invented and rebuilt once you have your focus-the business model if you will-in your mind. In the case of this '67, the new road wasn't a huge departure from the 6-lane highway of stock, but it nevertheless was a road less traveled. Not for any one reason, but likely because of its uncertainty as to where it leads, or the possibility of some speed bumps and potholes to be navigated. Our instructions from the car owner were; at least four hundred horsepower, pump gas friendly, a rowdy personality, fuel injection, and-oh yeah-it all has to fit under my small block hood. Where the hell do you find that road on a map? We thought, of course,about the LS series engines with their proven performance and reliability. But the only engine that came to mind with the rowdy personality-and able to deliver that kind of performance-was GM Performance Parts' ZZ383, with an idle quality that speaks the language of potato-potato-potato.