Mustang Club of Maryland

What Is A Stroker Engine Anyway?
Dial More Displacement Into Your Engine Build
January, 2001 issue of Mustang Monthly

Making more power boils down to how much energy we can glean from the compressed air/fuel mix. The more volume we can huff into the chamber, the more power our engine is going to produce. We compress more air and fuel with a supercharger, a larger carburetor or throttle body, bigger valves, or a greater amount of displacement. Greater displacement is likely the cheapest way to pull power from a given block and cylinder head combination.

Strokers have always been the swiftest path to displacement and power. And engine builders have been building strokers for ages. Take the 289/302 engine block, for example. Did you know that you can infuse up to 355 ci into this block? The nimble 351W can be pumped up to 429 ci. Just imagine, big-block power from a small-block. Larger mills, such as the 429ci big-block, can be stroked up to more than 500 ci—talk about power!

When you’re rebuilding a Mustang’s V-8 engine, you can increase the displacement with a stroker kit without anyone being the wiser. What’s more, stroker kits don’t cost any more to build. Add to this their convenience and you’re ready to build in cubes. Stroker kits are available already machined and ready for assembly. In some cases, all you have to do is prep the block, which can be accomplished through your local machine shop. In fact, we suggest that your machine shop handle the entire build-up, checking all tolerances before complete assembly.

What Is a Stroker?
As its name implies, a stroker is where we increase engine displacement by increasing piston stroke. When we increase stroke, we take the piston deeper in the cylinder bore, which increases displacement. The longer the stroke, the greater the fuel/air charge. Because mechanical advantage or leverage comes with stroke, torque does too. Think of stroke as you would using a breaker bar instead of a ratchet to remove a stubborn bolt. The longer the lever--or stroke--the greater the mechanical advantage.

We can stroke an engine in a number of ways. One way is to offset-grind the crankshaft rod journals, adding some meat at the top of the rod journal, then grinding the journal true again. This adds stroke, even if it's just 0.020 inch. This might not seem like much, but it can add up to significant displacement increases. Remember, Ford stroked the 289 0.013 inch to achieve 302 ci.

Another way to achieve stroke is to machine a larger crankshaft down to fit a smaller block. The 347ci stroker is designed this way. We take a 351W crankshaft, machine the main journals and counterweights to fit the 289/302 block, and we end up with a 347ci stroker. The same is true for the 408ci stroker from a 351W block. A 400M crankshaft is machined down to fit the 351W block. Stroker kits often go even further, using Chrysler or Chevrolet connecting rods to achieve stroke. Piston wrist-pin height is another means, which calls for the use of custom pistons.

Stroker kits make obtaining displacement a no-brainer, because all you provide is the block--and in many cases, the manufacturer provides the already machined block, making short work of displacement. Stroker kits involve custom-ground pistons machined to clear valves and lower compression.

289/302 Small-Block Stroker Kits
Stroker kits for the 289/302 are plentiful, ranging from low-buck budget to the high-priced spreads for racing applications. Your mission and your budget directly determine what kit is best for you. Resist the temptation to order the greatest displacement available for your block, because it may not be appropriate. If you're going to push the engine, opt for better rods, pistons, and a steel crank. Weekend racers and cruisers will live fine with a cast crank and factory-style I-beam connecting rods.

Ford Performance Solutions 317 ci
302 block
3.100-inch stroke
High-nodular-iron early 302 crankshaft
Eagle 5.400-inch connecting rods
Ross ultralite forged pistons
Clevite 77 main and rod bearings
Childs & Albert piston rings
Kit price: Starting at less than $1,800

Nowak Racing Engines 327 ci
302 block
3.200-inch stroke
Australian 302 nodular-iron crankshaft
Eagle 5.400-inch connecting rods
Nowak forged-aluminum pistons
Michigan 77 main and rod bearings
Childs & Albert or Speed-Pro piston rings
Kit price: Starting at less than $2,500

Coast High Performance 331 ci
302 block
3.235-inch stroke
Early 302 nodular-iron crankshaft
English Ford 1,600cc engine
5.200-inch connecting rods
Probe forged-aluminum pistons
Clevite 77 main and rod bearings
Kit price: Starting at less than $2,000

Ford Racing Technology 347 ci
302 block
3.400-inch stroke
Cast-steel crankshaft
4340 steel 5.315-inch connecting rods
Wiseco forged-aluminum flat-top pistons
Clevite 77 main and rod bearings
Childs & Albert piston rings
Kit price: Starting at less than $2,000

Ford Performance Solutions 347 ci
302 block
3.400-inch stroke
High-nodular 351C crankshaft
Eagle 5.400-inch H-beam rods
Ross ultralite forged-aluminum pistons
Clevite 77 main and rod bearings
Childs & Albert piston rings
Kit price: Starting at less than $2,500

Coast High Performance 347 ci
302 block
3.400-inch stroke
Cast-steel crankshaft
Blue Thunder 5.315-inch I-beam rods
Probe forged-aluminum pistons
Clevite 77 main and rod bearings
Childs & Albert piston rings
Kit price: Starting at less than $2,000

Speed-O-Motive 357ci
302 block
3.500-inch stroke
351C nodular-iron crankshaft
Eagle 5.400-inch connecting rods
Ross custom-forged pistons
Clevite 77 main and rod bearings
Speed-Pro piston rings
Kit price: Starting at less than $2,500

351W Stroker Kits
It's nearly impossible for us to believe that you can almost stuff a 430 ci into a 351 Windsor small-block. Just imagine, big-block power from an engine the size and weight of a 351W. It gets us excited too. You can keep your '69 Mach 1 looking dead stock outside, while breathing big-block cubes inside. Just imagine the bewilderment your buddy in the Crap-aro is going to feel when you spank his 350ci RS/SS, while going through the traps Saturday night. This is the beauty of a stealthy stroker.

Nowak Racing Engines 377 ci
351W block
3.680-inch stroke
351W nodular-iron crankshaft/offset ground
Chrysler I-beam 6.125-inch connecting rods
Nowak forged-aluminum pistons
Michigan 77 main and rod bearings
Childs & Albert or Speed-Pro moly piston rings
Kit price: Starting at less than $1,500

Coast High Performance 408 ci
351W block
4.000-inch stroke
Nodular-iron 400M crankshaft
Eagle 6.200-inch connecting rods
Probe custom-forged pistons
Clevite 77 main and rod bearings
Childs & Albert piston rings
Kit price: Starting at less than $2,200

Ford Performance Solutions 408 ci
351W block
4.000-inch stroke
High-nodular 400M crankshaft
Pro H-beam 6.125-inch connecting rods
Ross ultralite forged pistons
Clevite 77 main and rod bearings
Kit price: Starting at less than $1,800

Ford Performance Solutions 426 ci
351W block
4.170-inch stroke
High-nodular 400M crankshaft
Pro H-beam 6.125-inch connecting rods
Ross ultralite forged pistons
Clevite 77 main and rod bearings
Kit price: Starting at less than $1,800

Speed-O-Motive 426 ci
351W block
4.170-inch stroke
Nodular-iron 400M crankshaft
Eagle 6.125-inch connecting rods
Ross forged-aluminum pistons
Clevite 77 main and rod bearings
Speed-Pro piston rings
Kit price: Starting at less than $2,000

Performance Automotive Warehouse (PAW) 427 ci
351W block
4.125-inch stroke
400M crankshaft
I-beam forged-steel connecting rods
Clevite 77 main and rod bearings
Sealed power moly piston rings
Kit price: Starting at less than $2,500

385-SERIES BIG-BLOCK Strokers
If your objective is ground-pounding twist and shout, there's nothing quite like a big bore and long stroke to get the job done. The 385-series engine family can handle upward of 550 ci--given your budget, a custom crank, rods, and pistons. Because we understand the importance of budget for your mild-mannered street stormer, we're going to focus on affordable stroker performance.

Coast High Performance 501 ci
429/460 block
4.160-inch stroke
460 nodular-iron crankshaft
Eagle 6.800-inch connecting rods
Probe forged-aluminum pistons
Clevite 77 main and rod bearings
Kit price: Starting at less than $2,500

What About the FE?
If your Mustang has an FE-series 390 or 428 Cobra Jet, you're likely wondering what's available to pump displacement into these classic big-blocks' time that the aftermarket seems to have forgotten. You can stroke a 390 High Performance using a 428 crankshaft to achieve 410 ci, just as Mercury did in 1966-'67. If your dear and late Uncle Ned left you boatloads of cash when he punched out recently, you can stroke the 427 block using a 428 crank to round up to 454 ci.

Because most FE blocks have experienced at least one rebuild in their service life, you can count on at least one overbore to 0.030 inch oversize. The FE big-blocks--except for the 427--will accept generous over bores up to 0.060-inch oversize. Because the 427 reaches the limits of the FE block with a 4.23-inch cylinder bore, the most they will accept is 0.020-0.030-inch oversize without flash floods. By the way, the 428 crank can be offset-ground to achieve a modest stroke increase.

Read more: http://www.mustangmonthly.com/techartic ... z1ksXgjHWo

_________________