photos 1, 2 I was lucky to have a set of blueprints to start this project with, instead of having to draw up a template myself. A good friend and fellow 240Z racer is a bridge engineer, and he provided me with this schematic. Supplies and costs: 24″x24″ sheet of .025″ 5052 anodized aluminum – $25, 6″ long x 3″ diameter thin wall aluminum tube – $5, three holesaw drill bits (for carb inlet, carb vent, and ductwork)- $35, various hardware bits – $20. Two days of shopping, drilling, cutting, filing, riveting, fitting, cursing, bleeding – priceless.
… 
photos 3, 4, 5 With a three carb setup, don’t assume they are in perfect alignment. Running a straight edge along the mounting bolts, I discovered one carb is slightly out of alignment with the other two. Take the time to check your math before getting out the tools. As my Dad always told me “measure twice, cut once”.
… 
photos 6, 7, I went down to my local, small town airport, and used a sheet metal brake at an A&P shop to put the initial set of 90 degree bends in the airbox.
… 
photos 8, 9, 10 After notching the corners, further bends were done with a block of wood and a hammer. I had the airbox on and off dozens of times to get the fit just right. I discovered all sorts of interference from brackets, supports, brake master cylinder bleed nipples, wiring looms, etc. I spent more time custom fitting than building. But I couldn’t just make the airbox smaller to fix these problems, you need a minimum of 50% more room above your velocity stacks than they are tall for proper airflow into them. In these pics you can see a sheet of removable white vinyl covering on the aluminum sheet.
… 
photos 11, 12 Cutting a 3″ hole in the firewall to feed the airbox through the cowl vent might be more carnage than some would care to inflict upon a vintage race car, but she’s my continuous project-in-the-works rolling laboratory, so some collateral damage is inevitable. The final outcome is pretty cool however, and a lot cheaper than the $400 TWM airbox that was an option. I’ll let you know how it works when I get her back on the track next month.
… 
Leave a Reply