Our good friends at Mast Motorsports are happy to release final flow numbers on their incredible 12-degree L92 heads available for small (3.90"), medium (4.00-4.07"), and large bore (4.125" or larger) LS motors. They've even been working on their own LS7-style head...all of which are available with the LSX block bolt pattern.
LS3/L92/L99 Small Bore:
Flow Data w/ 3.900" Bore Plate
Lift Intake Exhaust
.100 76 57
.200 147 110
.300 218 172
.400 274 214
.500 318 234
.550 333 242
.600 342 248
.650 349 252
.700 353 257
Flow Data w/ 4.000" Bore Plate
Lift Intake Exhaust
.100 74 61
.200 146 119
.300 222 188
.400 282 219
.500 330 236
.600 360 251
.700 372 260
LS3/L92/L99 Large Bore:
Flow Data w/ 4.125" Bore Plate
Lift Intake Exhaust
.100 78 65
.200 162 118
.300 243 171
.400 304 212
.500 347 229
.550 362
.600 376 245
.650 384 247
.700 390 249
LS7 4.125"+ Bore:
Flow Data w/ 4.125" Bore Plate
Lift Intake Exhaust
.100 76 65
.200 163 118
.300 245 171
.400 307 212
.500 350 229
.600 379 245
.650 388 247
.700 395 249