B/B Chev Big M2 Sportsman Engine Block, 4.500" Bore, 10.200" Deck, 4-Bolt Main Caps 31223454 DA31223454 DART BIG M2 SPORTSMAN BLOCK Dart engineered the Big M to be the strongest, most reliable, and easiest to build big block on the market.
The Dart Big M2 is designed from the ground up as a true racing engine block which can be used with standard off the shelf big block components. The Big M2 is cast from premium high strength Iron and beefed up in all the critical areas. A competition oiling system ensures adequate lubrication to the main bearings at high RPM.
Standard 9.800”, 10.200” and 10.400″ deck heights
Standard 4.250”, 4.500”, 4.560”, 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)
Available in .400” raised cam
Uses +.300” tall GEN VI style lifters. Modifi cation for MRK IV style available
4-bolt main bearing caps in steel or ductile iron have splayed outer bolts for extra strength
Lifter valleyhead stud bosses help prevent blown head gaskets
Easy to install AN fitting oil gallery plugs
