Ford 306 Cam Swap

Words And Photos: Richard Holdener

Nostalgia is a funny thing. Case in point, the original muscle cars. Naturally, we fondly remember the hot muscle motors of the original muscle car era, but truth be told, are these memories tainted or otherwise artificially enhanced by nostalgia? As powerful as the original Mustang, Camaro, and Challenger motors were, the new ones are even better. This should actually come as no surprise, as time and technology have marched rapidly on. For Ford fans, this means a new 5.0L Coyote is head and shoulders faster than even the hottest Shelby versions back in the late ’60s and early ’70s. In fact, taking one short step back in time, to the beginning of the second muscle car era, even the original 5.0L fuelie motor introduced in 1987 (we discount the 1986 version) could more than hold its own against any production small block from the late ’60s and early ’70s. Not only was there plenty of performance, but the little injected 302 also improved things like drivability, fuel economy, and emissions production.

As we know, the popularity of that fantastic 5.0L gave Ford performance a serious shot in the arm, and even spawned one serious aftermarket industry. To this day, building a stout small block is as easy as picking up the phone. Though the 5.0L guys took — and continue to take — this for granted, old timers can remember a day when the only option for your hot Ford small block was a worked-over set of 1969 351W castings. Today, if you look to build a 302 (or 351W), you can choose from as many as 30 different available cylinder-head combos. The same can be said of available intake manifolds and camshafts for the 5.0L.

We also recognize that hopping up a Ford 302 isn’t just for 5.0L Mustang owners, as the little 302 has a well-deserved reputation of power, affordability, and packaging. The thin-wall casting makes for a lightweight combination for someone looking to swap a V8 into an import or even domestic application originally equipped with a wimpy little four pot or six cylinder.

No matter what you plan to do with it, we know a 5.0L Ford V8 is always a good starting point. Though any 302 is a decent performer in stock trim, our test involved upgrading a crate motor from Blue Print Engines. Blue Print makes it easy to create Ford power; just grab your credit card and get on the phone.

The bp306sp crate motor used for our cam test originally came as a short block. The 302-based combo produced 306 inches thanks to a .040 over bore. The short block also included 5.155-inch rods and flat-top, hypereutectic pistons. The lack of forged internals didn’t worry us one bit, having already run a ZEX nitrous kit on this motor. For our needs, the BPE short block came with an already healthy hydraulic roller cam (.543/.554, 218/226, 112 lsa), lifters, and a front cover. Though it made effective power when combined with the aluminum heads and our chosen induction system, we would be replacing it with an even more powerful grind.

Since the BPE 306 was originally supplied as short block, we needed a few things to complete it, including aluminum heads, roller rockers, and an induction system. For head flow, we turned back to BPE for a set of their as-cast, aluminum 190cc castings. The heads (hp9008) combined a 2.02/1.60 valve package with 60cc combustion chambers and offered impressive flow, with peaks topping 250 cfm on our bench. Topping the heads was a dual-plane, Eliminator intake from Speedmaster. A dual-plane should be the first choice for any sub-6,500-RPM, street 302 combination. The final touches included a 650 carb, billet distributor, and 1 ¾-inch, long-tube headers. Also present was a Meziere electric water pump, Lucas 5W-30 oil, and COMP Cams composite valve covers.

Run with the cam supplied by Blue Print Engines, the 306 produced peak numbers of 371 HP at 6,100 RPM and 367 lb-ft of torque at 4,000 RPM. The combination worked well, especially given the mild cam timing and as-cast heads, but we knew there was more power to be found in the little small-block Ford, so we decided to upgrade the cam.

After running the little 306 with the mild cam supplied with the short block, we decided to install a COMP Cams XE274HR grind. A favorite of ours for many reasons, the 274 cam has always proven itself both powerful and drivable. It offered a .555/.565 lift split, a 224/232-degree duration split, and 112-degree lsa. Even on a small 302, this cam was every bit at home in a daily-driven, fuel-injected 5.0L as it was in a street/strip stormer.

After removal of the original cam and installation of the XE274HR, we were rewarded with a sizable increase in power. The new cam increased the power output of the 306 from 371 HP and 367 lb-ft of torque to 393 HP and 369 lb-ft of torque. Note that the torque peak changed by a scant 2 lb-ft, but the power output increased by over 20 HP. We also liked the fact that the cam swap came with no loss in low-speed torque, meaning we would never have to wait for the motor to come up on the cam. Just like any motor, the right cam makes all the difference in the world.


Graph: XE274HR Cam Swap- 306 Ford

This is what we like to see when swapping a cam. Replacing the BPE crate-motor cam with the XE274HR grind from COMP Cams resulted in a sizable gain in power. Run with the supplied cam, the 306 Ford produced 371 HP at 6,100 RPM and 367 lb-ft of torque at 4,000 RPM. After installation of the XE274HR cam, the peak numbers jumped to 393 HP at 6,400 RPm and 369 lb-ft of torque at 4,300 RPM.  Note there was no loss in low-speed torque with this cam swap.