Genuine MRP Part
-Billet EN10025 Structural Steel
-Greatly increases block rigidity
-Works with 4age OEM windage tray and 4age Sump (does not work with 7afe oil sump)
-Dual sump bolt pattern to suit 16v/20v (Also fits 7a blocks)

From MRP themselves:

The 4age blocks lack lateral support at the crankshaft center line. This lack of support can lead to the block and crankshaft bending under high loads. This can lead to excessive bearing wear and block failure. MRP main bearing girdle prevents distortion and misalignment of the main bearings under extreme performance applications.

If you have an expensive engine build shooting for extremely high revs, or more than 300hp on a 4ag, this is a necessary add on for a reliable bottom end.

**Requires a UNIQUE ARP Main Stud kit (NOT 4AGE).  Select ARP studs when checking out if you would like a package price**