5.0 Mustang & Super FordsHow To Engine
Stick Swap: 5.0 Camshaft and Valvetrain Upgrade
Give your stock 5.0's torque numbers a lift with Crane's PowerMax 2020 camshaft and roller rockers
Horse Sense: Cam swappers should be aware of the importance of selecting the right camshaft. The super-lopey, high-lift cam you think is your ticket to low e.t.'s might be the very thing that makes your 'Stang even slower than it was before you made the change.
That cam sounds gooood! - is usually the unanimous statement of approval at car gatherings, the track, in the shop-pretty much anywhere-whenever the rumble of a cammed, small-block Ford is heard. Man, there's something about the lope of a hot bumpstick. The sound can make many a 'Stangbanger salivate like Pavlov's dog, and forces even novice enthusiasts to say, "Whatever's under the hood of that thing definitely isn't stock!"
Selecting and purchasing a performance camshaft are among the first internal-engine upgrades a 5.0 enthusiast makes when he embarks on the road to improving his Pony's performance. In a conventional, pushrod 5.0 engine, the cam is the long, forged-steel rod with round and egg-shaped lobes (one lobe per each valve) that runs through the center of the engine block from front to back. The camshaft's role is to actuate all the components of the valvetrain (lifters, pushrods, and rocker arms) that control the operation of the intake and exhaust valves. By opening and closing at points initiated by the camshaft's timing profile-after, and before bottom dead center and top dead center-the valves let in the air/fuel mixture and send exhaust gasses out of the combustion chamber.
We wanted to see what kind of performance difference installing a good, street camshaft would make on a stock 5.0 Mustang. We also wanted to show newcomers to 'Stangbanging one of the easier bolt-on projects that can be accomplished in the driveway or home garage. Mrs. Fumiko Alston owns-yes, it's her car, not her husband's-the virgin '93 GT convertible with AOD we used for our cam swap. The 'Stang, which Fumiko affectionately calls "Red Ruby," was a daily driven, untouched ride we knew would be perfect for this project.
With Fumiko's blessing and assistance from her husband, Ward (who owns and races an '88 hatch GT in NHRA's Stock Eliminator category), we installed a PowerMax 2020 camshaft (PN 444211), hydraulic roller lifters (PN 36530-16), and a roller timing chain (PN 44975-1) package from Crane Cams we hoped would give the 'vert more zip on the freeway and put a "not-stock-anymore" burble in the exhaust note. Follow along as we take you through the project.
Cam Swap Tips
While changing a cam isn't that difficult on a 5.0 Mustang, there are still a few things you can do to help make things go smoothly. We recommend you try these tips.
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.
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.
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.