M Sportsman BBC Block
31273344, 31273354, 31273444, 31273454, 31273644, 31273654
deck heights and bore sizes up to 4.600", the Big M Sportsman
block gives you the versatility to build a wide variety of engine
combinations. A true priority main oiling system oils the main
bearings before the lifters for extra reliability.
Standard 9.800" and tall 10.200" deck heights available
for stroker engines.
Standard 4.250" , 4.500" or 4.600" bore sizes with
siamesed extra thick cylinder walls to resist cracking and improve
ring seal (minimum .300" thick with 4.625" bore).
Uses +.300" tall Gen VI style lifters. Modification for Gen
IV style available.
Scalloped outer water jacket walls improve coolant flow around
the cylinder barrels to equalize temperatures.
4 bolt ductile iron main caps have splayed outer bolts for extra
True priority main oil system lubricates the main bearings before
the lifters. Our stepped main oil gallery (9/16" to 1/2"
to 7/16") increases the flow of oil to the crank at high
rpm, and our front oil crossover eliminates internal oil leaks
around the distributor shaft.
Oil filter pad is drilled and tapped for an external oil pump.
Lifter valley head stud bosses prevent blown head gaskets.
Rear main cap uses standard oil pump and two piece seal - no adapter
Mechanical fuel pump boss, clutch linkage mounts, and side and
front motor mounts simplify installation in any chassis.
Dual oil pan bolt patterns fit standard and notched oil pans.
Coated cam bearings, freeze plugs and dowels are NOT included.
Dart blocks are available fully finish prepped.