Y-BLOCK DISPLACEMENT CHART
STROKE
Crankshaft 239/256 272/292 312 312-2.10" See notes
3.10" 3.30" 3.44" 3.51" 3.64" 3.70"
BORE ford-y-block.com
3.50" std. 239 239 254 265 270 280 285
3.53" +.030 239 243 258 269 275 285 290
3.54" +.040 239 244 260 271 276 287 291
3.56" +.060 239 247 263 274 279 290 294
3.62" std. 272 256 272 283 289 300 307
3.65" +.030 272 259 276 288 294 305 310
3.66" +.040 272 261 278 290 295 306 311
3.68" +.060 272 264 281 293 299 310 315
3.75" std. 292 274 292 304 310 322 327
3.77" +.020 292 277 295 307 313 325 330 ford-y-block.com
3.78" +.030 292 278 296 309 315 327 332
3.79" +.040 292 280 298 310 317 329 334
3.80" std. 312 281 299 312 318 330 336
3.81" +.060 292 283 301 314 320 332 337
3.83" +.030 312 286 304 317 324 335 341
3.84" +.040 312 287 306 319 325 337 343
3.86" +.060 312 290 309 322 329 341 346
3.875" Custom 292 311 324 331 343 349
3.912" Custom 298 317 331 338 350 356
NOTES: ford-y-block.com
For 256 use 272 bores with 3.10" stroke.
3.10" stroke is "EBU" crankshaft from ’54 55 239 or ‘54-55 256 cubic inch engines.
3.30" stroke is "EC" crankshaft from ‘55-57 272 or ‘55-64 292 cubic inch engines or C1TE steel crank..
3.44" stroke is "ECZ" crankshaft from ‘56-60 312 cubic inch engine.
3.51" stroke is "ECZ" crankshaft offset ground to 2.100" rod journal for aftermarket
connecting rods. Assumes starting with .020" undersize journal.
3.53" is maximum offset with standard diameter rod journal.
3.64" stroke is accepted maximum stroke. Some rod/camshaft interference. Clearance rods as required.
Longer than 3.70" strokes require reduced base circle cams or 2.00" rod journals,
additional clearance grinding of connecting rods #1-3-5-7. Equalize weight of
#2-4-6-8.
Not shown. Standard 3.30" stroke cranks can be offset ground to 3.41 stroke.