How to Stroke Any Engine - Stroker Science

Cylinder Blocks

The difficulty with a longer... 

   

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The difficulty with a longer stroke is that the connecting rod travels in a wider arc. The arrow points to where this small-block Chevy block was relieved to clear the connecting-rod bolt. This is delicate work, since water jackets lurk near where this grinding takes place on a production block.

The majority of street stroker engines built in the world today are based on production blocks. The trick for stuffing a stroker crank in an OE block is all a question of architecture. Assuming the crank main journals will fit or can be machined to fit the block in question, the next biggest hurdle is whether the counterweights will clear. Often, connecting rods can be troublesome because they tend to hit either the side of the crankcase, the camshaft, or both. This necessitates machining the block to clear the rods or custom stroker-style rods. A longer stroke may also require a custom oil pan to clear the additional width of the rotating assembly.

If you're really serious about a stroker motor, the ideal move may be to step up to an aftermarket block. While the more popular engines like the small-block Chevy and Fords offer a dizzying assortment, there are more blocks coming on line every day. There's even an aftermarket block from Indy Cylinder Heads for the AMC 401. For stroker motors, these aftermarket blocks generally offer more crankcase room for longer strokes accompanied by huge bores. The standard-deck-height Ford Racing 460 block, for example, makes up to 598 ci with a bore of 4.600 and a 4.500-inch stroke.

Monsters of the Midway
We thought it would be fun to look inside the biggest automotive V-8 race engines on the planet. There may be bigger ones out there, but it would be tough to top a 900ci Hemi Ford engine that Jon Kaase built for a tractor-puller customer. According to Kaase, the normally aspirated engine makes a neck-straining 1,400 lb-ft of torque. At 900 ci, that means each cylinder displaces 112.5 ci-or just a little bit less than three times those of a 5.0 Mustang V-8.

Aftermarket Blocks For Stroker Applications
Here are some common blocks and deck heights. The ones listed as "tall-deck" have deck heights taller than stock to accommodate longer rods for long-stroke cranks. There are many more part numbers available than those listed, as many blocks are also available with various bore sizes and main-cap styles.