Mercury Racing 525 replacement style heads. Three intake runner sizes offer potential for increased levels of performance. We’ve retooled Dart’s PRO1 BBC castings to produce a true bolt on upgrade for the Mercury Racing 525 engine. The PRO1 24° 525 MMR is available with 310cc, 325cc or 345cc intake runners and has the correct exhaust bolt pattern for the factory manifolds. A grey chromate surface treatment inhibits salt corrosion for marine usage.

More From This Category

AFR Cylinder Head, 14° BB Ford 315cc Fully CNC ported, 85cc chambers, .250 Raised Exhaust Port Location, assembled w/ 1.550 OD Hydraulic Roller

AFR Cylinder Head, 14° BB Ford 315cc Fully CNC ported, 85cc chambers, .250 Raised Exhaust Port Location, assembled w/ 1.550 OD Hydraulic Roller

$6,100.10

View
World Cylinder Head, Sportsman II, Cast Iron, Assembled, 64cc Chamber, 200cc Intake, For Chevrolet, 302, 327, 350, 400, Each

World Cylinder Head, Sportsman II, Cast Iron, Assembled, 64cc Chamber, 200cc Intake, For Chevrolet, 302, 327, 350, 400, Each

$1,545.00

View
Dart Cylinder Head, Assembly, 360 Super Mod, 2.325/1.900/1.625D 4.310, Each

Dart Cylinder Head, Assembly, 360 Super Mod, 2.325/1.900/1.625D 4.310, Each

$3,640.47

View
Dart Cylinder Head, Pro1 Chevrolet LS Gen III, 250.00 CC Port, 68.00 CC Chamber, Each

Dart Cylinder Head, Pro1 Chevrolet LS Gen III, 250.00 CC Port, 68.00 CC Chamber, Each

$3,608.45

View
World Products 053030-3 – Cylinder Head Cast Iron Ford Small Block WINDSOR JR. 180cc 58cc 20Degree 1.940″ x 1.600″, Assembly w/ 1.500″ springs for sol

World Products 053030-3 – Cylinder Head Cast Iron Ford Small Block WINDSOR JR. 180cc 58cc 20Degree 1.940″ x 1.600″, Assembly w/ 1.500″ springs for sol

$1,497.67

View
World Cylinder Head, Sportsman II, Cast Iron, Bare, 72cc Chamber, 200cc Intake, For Chevrolet, 302, 327, 350, 400, Each

World Cylinder Head, Sportsman II, Cast Iron, Bare, 72cc Chamber, 200cc Intake, For Chevrolet, 302, 327, 350, 400, Each

$960.89

View