Stick Swap: 5.0 Camshaft and Valvetrain Upgrade

Camcyclopedia

Extreme Automotive uses a... 

   

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Extreme Automotive uses a Dynapack Evolution 4000 chassis dyno for real-world recordings of a Mustang's all-important rear-wheel horsepower and torque output. Unlike a roller dyno, the Dynapack unit accurately accounts for every rotation of the axle without any possibility of losing power or torque from tires slipping or fluctuations in load and rpm signals to its processor. Extreme's Saul Guttieriez performed the baseline and post-installation dyno runs on Red Ruby.

Selecting the best camshaft for your engine combination and performance desires is a lot easier when you understand the information on the cam card. Camshaft duration and lift specs are oftentimes talked-and bragged-about, but they make up only half of the crucial characteristics of a camshaft. The four crucial camshaft specs to understand are duration, centerline, lobe separation, and lift.

Duration refers to how long a valve is opened in relation to crankshaft rotation. This time period is quantified in degrees of crankshaft rotation. So, our Crane cam's duration specification of 208 degrees (intake) and 216 degrees (exhaust) duration at 0.050 inch of lifter rise (the industry-standard lift point at which duration is defined because it's a consistent value) means the cam holds the intake and exhaust valves off their respective seats for 208 and 216 degrees of crankshaft rotation.

Duration can be helpful for high-rev engines, but lower-rpm powerplants won't benefit from the cam being stocked with duration. The longer the valves stay open in a high-rpm motor, the more time airflow has to get in and out of the cylinders. On the low-rpm side, a lot of duration hinders power output because the valves can open at the wrong time in relation to the piston's stroke (up or down), which causes some of the cylinder-charge escape.

Dyno Results

The 'vert's initial power... 

   

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The 'vert's initial power output was dismal, so the call was made to hop up the stock 5.0 with a few of the tried-and-true "free horsepower" tricks we learned many moons ago. A little timing (13 degrees) and unfiltered airflow did the trick. We decided there was no way we were going to dyno the car again without a fresh set of plugs and a new air-filter element to complement the new camshaft.

Fumiko's convertible was a startling reminder of what the term bone stock really means. After connecting the rear axles to Extreme Automotive's Dynapack Evolution 4000 chassis dyno, the little red 'Stang gave us a disappointing surprise when it mustered a feeble 120.72 rear-wheel horsepower and 161.54 lb-ft of torque on the first hit (our optimistic forecasts were for at least 160 hp at the rear wheels-so much for wishful thinking). As the car was 100 percent OEM Ford, and since the engine's tune-up history was not quite clear (this thing was still rolling on only 8 degrees of timing and the plugs had seen better days), we decided to at least make a few of the basic "free" power tweaks in an attempt to make the baseline numbers a little more respectable. After adding timing (we stopped at 13 degrees) and removing a dirty air filter, we were able to reach an improved 138.57 rear-wheel horsepower and 185.10 lb-ft of rear-wheel torque. Based on the warm, low-90-degree temperature inside the dyno stall, the stock AOD tranny and converter, and Red Ruby's poor state of tune, this was about as good as it was going to get.

Stock AOD transmissions (and... 

   

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Stock AOD transmissions (and their torque converters) are the dyno's nemesis. Although they're abbreviated, here are Red Ruby's pre-cam and post-cam numbers and graphs. Crane's PowerMax 2020 produced nice gains between 2,000 and 3,500 rpm where you'll feel them on the street. It's important to note that back in 1993, 5.0 'Stangs made an advertised 205 hp and 275 lb-ft of torque at the flywheel. On the chassis dyno, approximately 18 percent of flywheel power output is lost through the drivetrain, so we're taking this into account, as well as the time and attrition our stock tester has endured. The gains we saw (especially on the torque side) are actually pretty good.

Tuning a car on the dyno is definitely the most accurate method of dialing in an engine and learning exactly what's going on with a 'Stang's drivetrain. Extreme's dyno didn't hold anything back when it calculated our data. After some fine tuning to make sure we were on point with timing and to clear up a slight throttle-response issue, Saul put Red Ruby to the test. The cam really helped between 2,000 and 3,500 rpm before the stock induction and exhaust became a choke.

There's no way we can rule out the Crane camshaft's potential to make better horsepower numbers because it definitely will. Without using the engine's age and mileage (130,000) as an excuse for the small power gain-but considering that Fumiko's 'Stang has no other performance modifications-it's pretty much a given the power numbers will look a lot better when unequal-length short-tube headers and an after-cat exhaust (imagine trying to push air contained in a sealed box through a drinking straw), a hotter, high-output ignition, a better torque converter, and an AOD-friendlier 3.73 or 4.10 ring and pinion gears are added.

Dyno Numbers