1968 Plymouth Barracuda Drag Race Car - Wedged To The Max

Topping this combination off with an intake manifold also allowed us to show off one of our tricks. It's a given that for an engine of this size, we'll need a 4500 series carburetor. in fact, we've chosen a Barry Grant 1095 King Demon for the build, so a 4500 flanged intake manifold is what we need, right? Wrong. The guys at Indy discovered their 440-2 intake (4150 flange), combined with a 2-inch-tall adapter and mated to a 4500 carburetor, makes 12-to-15-more horsepower than the 4500 flange intake by itself. This combination does place the carburetor significantly higher, however, so if hood clearance is an issue, you may need to opt for the 4500 flanged intake. In the next of our two-part series on this build, we'll do some intake swaps at the track to see which intake really works best, but for our baseline we're going to use the 440-2 Indy unit with the spacer.

Now for the million-dollar question-what camshaft do we use to make the most of this combination? We assure you we don't take cam selection lightly, and much thought was put into which camshaft would optimize the parts we had selected for this build. Keep in mind, this engine is not a Dulcich dyno mule. It is going in a race car that will see regular duty nearly every weekend at the track, so it needs to have broad torque and power curves. As we stated earlier, our stock block will limit us to about 7,500 rpm, so we need to consider that, as well. Also, our car is no lightweight at 3,000-plus pounds, so an extreme, peak horsepower cam profile is out of the question. Also remember that consistency wins in bracket racing, and we still shift our own gears in this car so our cam needs to be somewhat forgiving if we miss a shift point by 100 or so rpm. Even though we had calculated our combination and had a good idea of the cam profile to run, we never make a cam selection without advice from the experts, so we called the engineers at Crane Cams to help us with our decision.

Crane has been in the camshaft manufacturing business since the first days of hot rodding. The engineers at Crane have designed cams for nearly every application you can think of, and their wealth of knowledge can greatly benefit your camshaft decision. For our combination, we already knew that we needed lift numbers in the high-.600 to low-.700-inch range just to make our engine breath properly. Going with a higher lift could make slightly more power, but would sacrifice longevity due to accelerated valvespring wear. The engineers at Crane also agreed that duration at .050-inch numbers needed to be in the 280- to 290-degree range to make the power we were asking from this motor. After further discussion with the guys at Crane, we decided on a custom ground solid roller stick with .715-inch lift on the intake side and .688 inch on the exhaust, and 284-degrees duration at .050 on the intake, and 296 degrees on the exhaust. Lobe separation is a wide 112 degrees, which our big-inch wedge should like, especially since it launches at 4,600 rpm and only sees lower revs than that when idling through the pits or staging lanes. This camshaft will make power at a fairly high rpm, but will still make the torque required to get our car moving out of the hole. Since we also use this car in local Quick 16 races and sometimes use nitrous oxide, this cam should be a great choice making good torque and power on the motor, but still taking advantage of the torque created by the nitrous when we squeeze the button.