Engineered for applications where water between the bores is a requirement. Siamese bore versions are also available for larger bore applications. (Tech Sheet)
MRK IV blocks use the 2-piece rear seal design, and Gen V and Gen VI blocks use a 1-piece rear seal as well as a different timing cover pattern.
These blocks are based on Dart’s Big M design and include features like priority main oiling and 4-bolt main caps.
- Standard 9.800” and tall 10.200” deck heights available.
- Standard 4.250”, 4.310”, 4.500”
- Uses +.300” tall Gen VI style lifters. Modification for Gen IV style available.
- 4-bolt main bearing caps in Ductile Iron have splayed outer bolts for extra strength.
- Lifter valley bosses for OE style roller lifters and retainer.
- Mechanical fuel pump boss, clutch linkage mounts, and side and front motor mounts simplify installation in any chassis.
- Parts kit sold separately
These blocks are available in any level of finish from ready for "as-produced" to fully machined to a complete custom crate engine. Whatever your needs, we can help.
Optional fully prepped block ready for assembly includes:
-Square deck to height and CNC chamfer cylinders on our 4-Axis Rottler CNC
-Deburr entire block & main caps
-Hone cylinders w/torque plate
-Align-hone mains, hone lifter bores
-Final clean block and paint with primer in your choice of colors
-Install cam bearings & test fit cam
-Install oil galley and freeze plugs
Our 4-axis CNC boasts precision of 0.0002" and one thousandth of a degree. Check out this Instagram time-lapse video of a probe cycle. While we do love our CNCs, we use old school stone hones for a finish we believe to be superior to that typical of diamond hones.
Pricing includes free standard shipping in the continental US.
Please call us at 815-725-2727 for questions and pricing on finish machining, short blocks, long blocks or full crate engines.
Buy your parts from people who use them!
While you are here, check out the video of a Big M build featured in Chevy Hardcore.