Who: Mike Robinson
What: '71 Maverick
Where: Easthampton, MA
Engine: This is a nonrebuilt '84 Ford 300 cube-six with 110,000 miles. It has the factory original head gasket, head bolts, 8:1 cast pistons, forged rods, cast crank, and a hydraulic flat-tappet F-150 pickup truck cam (0.368 lift, 192 duration at 0.050). Not original are the fresh HV oil pump and stock F-150 oil pan massaged for Maverick chassis. The stock, cast-iron head is unported and still runs O.E. 1.78/1.52 valves. The stock, single valvesprings have been replaced by Comp small-block Chevy triple springs (dampers removed), which fit the stock Ford valveguide bosses and keep turbo boost from blowing the valves closed. The stock, stamped-steel retainers and pushrods were reinstalled. Induction consists of a box-stock Offy cast-aluminum four-barrel intake manifold topped with a 600-cfm Holley double-pumper with mechanical secondaries and the power valve removed. A stock remanufactured Garrett TO4B from an International DT466 dump truck blows through the carburetor via custom-fabricated induction plumbing. Mike converted a pair of '88 Thunderbird Turbo Coupe intercoolers for water-to-air operation; a trunk-mounted 7-gallon ice-water tank and electric pump are used for coolant. Spark plugs are three steps colder than stock. Power is estimated at 380 to 400 hp at the tires (as calculated from the timeslip).
Fuel: Mike started out using VP 116-octane C-16 race gas but switched to VP Q-16 oxygenated gas and picked up 4 tenths. He says, "It sure stinks but is a key ingredient in keeping things alive. The oxygenated feature allowed me to become more aggressive with the timing and jump the boost from 5 to nearly 25 psi." In the carb, 95 and 99 primary/secondary jets work best. The trunk-mounted aluminum tank is internally divided to contain 15 gallons of gas and the ice water for the intercooler.
Transmission: Mike uses a vintage Fairbanks C6. A built C4 would reduce weight and consume less power, but Mike prefers the added durability of the C6. Both bolt directly to the back of any 300-cube Ford six. The converter is a 10-inch unit from Ultimate that stalls between 3,800 and 4,200 rpm. Here's Mike's launch technique: "I light the pre-staged bulb then slowly creep up on the second bulb using the throttle and foot brake. Then I activate the first stage of the MSD two-step rev limiter at 4,000 and mash the throttle to build boost. The four caliper rear disc brakes hold the car steady on the line, so when I release the brake pedal on the last amber bulb, the car launches hard. I up-shift into Second at 4,700 rpm then make the final to-drive up-shift at 4,900 and run through the traps at about 5,200 rpm."
Rearend: The aluminum driveshaft tube is from another project, shortened to suit the Maverick, with Spicer 1350 U-joints at both ends. The Ford 9-inch housing has 3 1/4-inch tubes of 1/4-inch D.O.M. material butted almost against the bearing caps for maximum strength. The Moser aluminum center has 3.25:1 gears, a spool, and 35-spline axles.
Exhaust: Thanks to the turbo's noise-damping characteristics, no muffler is required. A simple 4-inch downpipe runs from the turbo outlet beneath the nose of the car. This saves 50 pounds, and the exhaust note is perfectly acceptable—though at WOT it sounds like a UPS truck on acid.