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.
1 Mark Jeffrey at Trans Am...
1 Mark Jeffrey at Trans Am Racing is working with a C6ME 390 block that has been decked square, bored, honed, and line honed. It is amazing how much displacement you can pump into this block. The 4.050-inch bores have been cut and honed to 4.080 inches and will get Trans Am Racing’s 4.250-inch stroke to achieve 442 ci.
2 ARP main studs are installed...
2 ARP main studs are installed for main cap stability. Bolt holes have been chased and lubricated. Get studs within 1?8-inch of bottom, but do not bottom out. Stud tension and security come when torquing the main caps.
3 Mark goes with screw-in...
3 Mark goes with screw-in oil gallery plugs in vulnerable places where critical oil pressure could be lost. He fabricated this special extended tap just for FE oil gallerys. It is suggested that all oil gallery plugs be screw-in, although not all engine builders do this. Make sure yours does.
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.
4 Oil gallery to bearing...
4 Oil gallery to bearing alignment is something that has always concerned us with FE big-blocks. When we asked Survival Motorsports' Barry Rabotnick, undoubtedly the most knowledgeable FE builder in the world, about this dynamic, he suggested chamfering the hole (countersink) to increase oil volume. However, he also added he'd seen a lot of them this way without consequence.
5 FE rear main caps are leak...
5 FE rear main caps are leak prone, which is why you must give them close attention. Rear main crank seals get Permatex Form-A-Gasket between seal and grooves, always with the seal lip turned toward the crank. Side seals get the same treatment. Mark also suggests sealer between the cap and block.
6 After the crankshaft is...
6 After the crankshaft is lowered into place, the bearings are dressed with engine assembly lube. Never use moly coat. Mark has opted for a 4340 steel crank with a 4.250-inch stroke, which will net 442 ci.
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.
7 Mark suggests never bottoming...
7 Mark suggests never bottoming out the studs, which can crack the block when torqued. Instead, get studs within 1/8-inch of bottom with clean lubricated threads. Then install main caps and torque the nuts one cap at a time beginning at #3. Torque caps in one-third values, checking the crankshaft for freedom of rotation with each cap. If you can't move the crank with your fingertips, something is wrong with the clearance.
8 Mark sourced this cam retainer...
8 Mark sourced this cam retainer from Carroll Shelby Engines, which isn't far from his shop.
9 Always check cam sprocket...
9 Always check cam sprocket to bolt head clearance, which should be a minimum of .060 inch. Camshaft endplay must always be checked when you check crank endplay.
10 Our Trans Am Racing stroker...
10 Our Trans Am Racing stroker package includes floating piston pins. The pin must glide nice and smooth through the bushing. If it is tight, it is unacceptable because you want an oil wedge between the pin and bushing. If it's too tight, you will fail.
11 These spiral wrist pin...
11 These spiral wrist pin retainers have been around for a while and are much safer than conventional C-clip retainers because, once installed, they don't come out, which means little chance of cylinder wall damage.
12 One area that stumps a...
12 One area that stumps a lot of home garage and professional engine builders alike is oil scraper ring and expander installation. You must follow the manufacturer's guidelines to the letter. Expanders are typically butt joined. Ring end gaps should be staggered 90 degrees apart or every 15 minutes on the clock.
13 Oil and compression ring...
13 Oil and compression ring installation is a personal matter because some engine builders roll them on while others use an expander. If you roll them on, you must be very gentle to install without distortion.
14 As with oil scraper rings,...
14 As with oil scraper rings, end gaps should be every 90 or 180 degrees apart.
15 To help provide improved...
15 To help provide improved piston ring seating during break-in, Mark uses Total Seal Quickseat dry powder assembly lube on cylinder walls.
16 When assembling a 390...
16 When assembling a 390 with a 4.250-inch stroke, it becomes apparent how much huff you can pump into this block. Although you don't have the 428's bore, you’ve got more stroke than the CJ.
17 The assembled short-block...
17 The assembled short-block shows the piston about .005-inch out of the hole, which will yield the compression Mark is seeking--around 10.5:1. Head gasket thickness, coupled with chamber size, determines compression ratio once you've determined compression height.
18 This one bites more of...
18 This one bites more of us than anything. "FRONT" means front with head gaskets. Head gasket coolant passages must go at the back of the block. Otherwise, you will experience overheating.
19 Mark has chosen Edelbrock...
19 Mark has chosen Edelbrock Performer RPM aluminum heads (NHRA castings, #60057), sporting 2.09/1.66-inch intake/exhaust valves. Out of the box, the heads flow 270 cfm at .600-inch lift. Intake runner volume is 170 cc. Exhaust is 125 cc. Chambers are 72 cc.
20 Mark performed extensive...
20 Mark performed extensive port work on the Edelbrock heads and managed to get 370 cfm from the intake and 194 cfm exhaust.
21 Ported Performer RPM NHRA...
21 Ported Performer RPM NHRA castings arrive bare, enabling you to fit them anyway you desire. Mark's port work reduces restriction and turbulence, making already terrific FE heads even better.
22 Mark uses ARP fastener...
22 Mark uses ARP fastener lubricant on the ARP cylinder head bolts for accurate torque readings, torquing the heads from inboard out in one-third values. And no matter what anyone will tell you, retorque heads at 500-1,000 miles after a good break-in.
23 Bar-style Comp Cams roller...
23 Bar-style Comp Cams roller tappets are lubed for installation. Mark carefully examined these lifters to determine which way the bar should be configured--toward the block or away. His conclusion was away from the cylinder bank and toward the valley to eliminate any risk of chaffing.
24 Like most of Mark's projects,...
24 Like most of Mark's projects, he's chosen MSD for the ignition system. This is the MSD billet distributor (#8595) with vacuum advance for street performance along with 8mm ignition wires (#31183) for reliability. The 8mm wires are universal cut-to-fit.
25 Holley and Edelbrock's Performer RPM team up to deliver the kind of horsepower and torque you might expect from a 442ci FE stroker. Holley's new Ultra HP performance carburetor (950-cfm, #0-80805HB) in Hard Core Grey is a new Holley four-holer experience because it's made from billet aluminum and loaded with design features--air bleeds moved outward for a smoother transition of air flow, easy to access fasteners, 6061T6 aluminum base plate with elongated dual pattern stud holes for standard and spread bore manifolds, fuel bowl drain plugs for easy service, redesigned 20-percent greater fuel capacity bowls, and knurled hand-adjustable idle speed screw.