Mustang MonthlyHow To Engine
Build A Stroker 390 FE
Settle an age-old Saturday night score with real horsepower, torque, and displacement
The sooner you come to terms with the reality of the Mustang's 390 High Performance V-8, the sooner you can get started building a better FE big-block. When you park the 390 Mustang and 396 Camaro side by side in a heads-up match race right off the assembly line, Camaro wins.
Because Chevrolet was interested in selling fast Camaros as much as Pontiac was hot to sell new big-inch Firebirds. And Chrysler didn't accept a back seat with its 383ci big-block Barracuda. AMC's Javelin and AMX 390 super cars were also quick. These marques all had Mustang in their crosshairs. The objective? Beat Mustang and grab a share of the lucrative pony car market.
Perhaps Ford became a little too comfortable with its head start in the marketplace. Or maybe product planners wanted a more sedate big-block for the Mustang's luxury image because the 390 wasn't much to write home about in terms of performance. It was basically Grandpa's Galaxie 390 with “GT” heads, which weren't much different from the Galaxie's aside from exhaust flange bolt patterns. Valve, port, and chamber sizes are the same.
Of course, you can build a vintage 390 Hi-Po for more power, including mechanical flat or roller tappets, 427 Medium Riser heads, and a healthy induction to make up to 450 horsepower. Or you can reach for the stars with this 442ci FE stroker that Trans Am Racing built for a client's '67 Mustang GT.
Stealthy, invisible spine-decalcifying power comes from this Trans Am Racing stroker kit that gives the Ford 390 FE a whopping 4.250 inches of stroke in the middle of a 4.130-inch bore, translating to bone-crushing torque. And if you're building a street/strip Mustang for Saturday night fun, this is a great engine package. It will provide startling amounts of torque, yet be well mannered on the open road. You can pump it up or tone it down depending on budget.
Let There Be Choice
When shopping stroker kits for a 390 or even a 428, you have a choice. Unless you are planning serious drag or road racing, or plan to use nitrous or forced induction, you don't need a steel crank with H-beam rods and forged pistons. Real power comes from increased displacement, stroke, and generous rod ratio. Stroke is what gets you snappy traffic light-to-traffic light performance along with respect-getting time slips. With stroke comes displacement along with greater mechanical advantage. Healthy rod ratio (length) gets you dwell time and an abundant air/fuel charge. So you don't always need steel and “H” to get torque. With a steel crank and H-beam rods, you get durability and room to grow power wise.
Trans Am Racing allows you to choose between cast and steel. If you're aiming for less than 500 horsepower, you can run a cast crank, I-Beam rods, and forged pistons to save money. Or you can opt for steel and H-beam durability along with the option of going to greater amounts of power in time.
Cam Profile = Tough Guy
An engine gets much of its personality from cam selection. Mark has a proven track record for coaxing unexpected amounts of power from his engine builds. Proof in the pudding is how his mills perform on the Westech dyno. For our stroker 390, Mark has selected the Comp Cams #33-000-9-FE-3122F/3122F HR110+4 custom hydraulic roller, which is actually a grind not routinely available from Comp Cams. This is a nice setup with a dual roller timing set and bar-style roller hydraulic lifters.
On the left is an adjustable pushrod checker from Comp Cams that makes light work out of figuring out valvetrain geometry. It enables you to set up rocker arm positioning so you can order just the right pushrod length and get your 390's rocker arms slap on the stem. On the subject of pushrods, spend the extra cabbage for one-piece pushrods for durability. This is a place you should never cut corners because pushrod failure can cost you plenty in engine damage.