Wilson’s Manifold Magic: Holley Hi-Ram for BlownZ

When it comes to intake manifold porting gods, there’s pretty much one name that floats to the top every time – Wilson Manifolds. Owner Keith Wilson has been porting intakes seemingly since the model “A” days, and there are few with the companies’ talent or experience to put your race engine in the winner’s circle. Wilson works manifold magic for some of the fastest drag racers (you’ve heard of Jason Line and Greg Anderson – right?) and NASCAR teams; but the unique thing about Wilson is that they will work magic for you. From carbureted intakes to race intakes, sheet metal intakes to accessories such as throttle bodies and spacers, Wilson has a full array of products for sportsman and everyday heads-up drag racers as well.

Step one in the Holley Hi-Ram Wilson project was removing the Holley plenum. Using a mill, Wilson’s fabricators cut out the stock runners from the original Holley plenum.

Shown here is the Holley EFI Hi-Ram intake manifold that we've been using on our LSX 388 that will serve as the basis for Wilson Manifolds intake layout.

(Left) This is a pretty shocking image: his is the Holley runners - shortened 3/4-inch, getting fitted and reconfigured for measuring for the plenum. When Wilson sent these images over to us, we gulped hard and simply had to trust them that they were going to get this thing finished up on time and on budget! (Right) Here, Wilson fits the sheet metal plenum to the Holley-Ram runners. Because we shortened the runners of the Hi-Ram, we had to re-angle and re-fit the plenum and runners together.

Those of you familiar with our 2002 Camaro BlownZ will know about our desire to run sevens with our ProCharger F-1R-equipped 388 LSX engine. As part of our mission, we equipped the engine with TFS 265cc cathedral port heads and the new Holley Hi-Ram intake manifold. The Holley Hi-Ram (see our article here) is an outstanding intake manifold that’s a tunnel ram-type intake for the LSX engine. However, because the Hi-Ram is built for everything from hot street applications (500 hp) to entry-level race engines, it simply can’t be all things to all people. After we got the engine running down the race track and on the dyno, we discovered that for our power levels of 1,300-plus horsepower, the Hi-Ram simply didn’t have the plenum volume that our engine needed in order to produce maximum horsepower with optimal efficiency.

This is the mock-up process of the sheet metal plenum. You’ll notice that there are no port openings yet, as Wilson scribes and then machines the port openings in the next stage of machining operations. The plenum is not yet welded to the runners at this point.

(Left) The Holley-Hi Ram runners were welded to the Wilson sheet metal base and, to make it look good, Wilson polished all of the welds flush and then bead-blasted the intake. This helps make the lower look uniform and aesthetically pleasing. (Center) Here, the upper part o the sheet metal intake is bring welded together. Everything Wilson touches that is aluminum is tig-welded by experts with years and years of welding experience. A fine touch is needed for welds that look awesome. (Right) During initial mock up, Wilson test fits the Hi-Ram with the new sheet metal plenum. Those vertical aluminum spacers are welded into the upper plenum area to keep the manifold from distorting and getting tweaked during the welding process. Wilson also shortened the Holley runners about 3/4-inch because of the 8,500 rpm range of our LSX intake.

Luckily for us, we had the phone number of our pals at Wilson Manifolds, and specialty sales manager and manifold expert Dave Secunda. Working with Secunda, we devised a plan for BlownZ’s Hi-Ram. The goal was to retain the Holley Hi-Ram intake runners construction and design, but to enlarge the plenum, and build a new sheet metal top for the Hi-Ram. Essentially, building the ultimate Hi-Ram. Since we’re planning on adding a ProCharger F-1X to our engine combination shortly, we told Wilson that we needed to be able to make up to 1,600 hp. So, consider this a Holley Wilson Hi-Ram designed to support 1,600 plus horsepower.

This is the finished upper sheet metal plenum that only needs to be final polished. Wilson calls this their ‘humpback’ design and it is engineered to allow the air to slow as it enters the plenum and turn into the first two runners. The goal here is enough plenum volume so that cylinders can all fill efficiently and completely.

(Top left) Another shot of the completed upper intake. This shot really shows you the humpback design. As air enters the throttle body and inlet area, the larger plenum opening (as you can see, the plenum is largest at this point vertically) slows the air and helps it turns into the initial 2-4 runners. (Top right) The completed lower plenum by Wilson after it has been fully bead-blasted. You can see how much work Wilson has put into the taper of the runners. (Bottom left) The completed Wilson Hi-Ram intake. (Bottom right) Another shot of the final Wilson Hi-Ram intake.

As we move forward in our racing endeavors, there’s no doubt that the modifications that the folks at Wilson Manifolds have performed on our Holley Hi-Ram will benefit us in the performance department as we take on the best that the East coast Drag Radial racing has to offer. But looking beyond the present, we’re now better equipped for our switch to the F-1X supercharger in the coming months, where we’ll be shoving a lot more air through that plenum and down into the combustion chambers.

About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
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