Do you remember when displacements above 400 ci were considered big-blocks? do you remember the overwhelming aura surrounding a big-brute Cobra Jet Mach 1 or Torino? When it comes to making power, there really is no replacement for displacement. In our quest to go faster, we've tried to shoehorn more displacement into big-blocks, arriving at nearly 600 ci with some of them. We've done the same thing with small-blocks, pumping as many as 429 ci into a 351W-based block. Aftermarket small-blocks allow even greater numbers, pushing 460 ci. The bonus here is mega-cubes without the penalty of weight. Translated-that's lots of available power from a lightweight package.
So why is it we don't just build a lot of big-inch small-blocks and throw away those old rotund big-blocks. Why do we even mess with an FE- or 385-series big-block anymore when we can stuff a boatload of displacement into something the size of a 351W? We asked Coast High Performance (CHP) this question.
Chris Huff of CHP suggested we build two engines using a nice combination of Coast High Performance and Edelbrock parts, and throw them on one of Vic's dynos. Two engines of similar displacement-a 351W bored and stroked to 427 ci, and a 390ci FE bored and stroked to 428 ci. Which of these engines will make more power and how? Let's find out.
Coast High Performance prides itself on building powerful Ford small-blocks. Truth is, CHP pioneered the modern stroker small-blocks-the legendary 347 and 427ci stroker small-blocks that have stood the world of drag racing on its ear over the past decade. Coast calls its line-up of powerful strokers the Street Fighter and Pro Street Fighter series. These engines were born for the lightweight, FOX-body Mustang crowd, but they're at home in any Ford engine compartment. As the Street Fighter name implies, these potent sticks of dynamite in small packages make all kinds of power right out of the box. Mix in nitrous or a healthy supercharger and numbers become staggering.
So how do we get 427 ci (or 8 liters) into a block designed for 351 ci? First, we increase the bore size a pinch or two. Next, we lay in a crankshaft with a greater rod journal throw, which really pumps up the displacement. Big-cube displacement comes from running the piston deeper into the cylinder bore for greater amounts of air and fuel. With that deep lungful, we also get the mechanical advantage that comes from greater leverage. The longer stroke gives our 351W greater leverage, just like we learned in high school physics class. With a long enough lever, you can move the world.
So what does shoehorning 427 ci into a Windsor block do for performance? It means as much as 500 hp and more than 500 lb-ft of torque when the go pedal is mashed. Depending on how you build your CHP 427W, it can be anything you want it to be. Pick the right camshaft, cylinder heads, and induction for trailer towing with your vintage Ford F-100 truck or Ranch Wagon. Opt for a more radical camshaft and deep-breathing heads for spine-decalcifying performance out of the traffic light. The beauty of a 427W Street Fighter is the versatility. You can build it anyway you desire and without the weight penalty of a big-block.
The 351W block sports five...
The 351W block sports five main bearings, just like the FE block. The advantage here is less weight because there is less iron. The FE's main bearing saddles wrap around the crank for better support.
The CHP 427 Street Fighter is available in two overbores: .030- and .060-inch oversize. We strongly suggest going with the standard 4.000-inch or 4.030-inch bore sizes for best results. Even though the 4.060-inch bore is available, we discourage this selection in the interest of solid engine integrity with a 351W small-block.
What Did It Do?
|Bore: 4.040 inch|
|Stroke: 4.170 inch|
|Facts:Cast Steel CrankshaftProbe SRS Forged PistonsOptional Dished & Blower PistonsCHP Beam Forged Steel Connecting RodsFlat Tappet High-Performance Hydraulic CamshaftEdelbrock Victor Jr. Induction System & HeadsEdelbrock 750-cfm CarburetorMSD Ignition SystemHigh-Volume Oil PumpDynamic BalancedVintage or Late-Model Ford Applications|
|Horsepower Tip: a roller camshaft would have pushed the 427W over 500 hp with over 500 lb-ft. of torque.|
The 351W's mains need the...
The 351W's mains need the lightweight support of a stud girdle if you are going to spin it tight. To accommodate the 427 stroker bottom end, Coast High Performance cuts some iron out of the cylinder skirts to clear the connecting rod bolts.
These bores are 4.060-inc...
These bores are 4.060-inches.
Pumping up the displacement...
Pumping up the displacement comes from a custom-ground cast-steel crankshaft, and forged rods and pistons.
Because we are increasing...
Because we are increasing compression height with greater stroke, we have to dish the piston to control compression.
Camshaft and valvetrain components...
Camshaft and valvetrain components come right off the shelf at Coast High Performance and Probe Industries. This flat tappet hydraulic bumpstick is .520"/.544" 234/244 112 LSA with a bit of a bump at idle. Open the throttle and watch out!
These are CNC-ported heads...
These are CNC-ported heads with 2.05/1.60-inch valves and 60cc chambers available from Coast High Performance.