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Competition Marine Designs, Inc.
Ph: (386)330-2420

Bushed Drum Housing

Double bushed 7075-T6 Connecting rod

Dynamically balanced Drum Valve

Large cooling capacity for Sport hydro's & Vee's

3 Transfers with Piston Ports

The MAC21 has the same bolt pattern as Novarossi, CMB and Picco

Heavy duty crankshaft bearings
Bore: 16.17mm
Stroke: 16.98mm
Rod Length: 31mm
Displacement: 3.49cc
Carburator: 9.0mm
Std. Plug head
Turbo head
- Optional
RPM: 28,000 - 36,000
Horse Power: 2.2 - 2.9
Current Records
IMPBA 21Hydro 1/3 mi. Oval - 18.86 sec., 63.62 mph.

NAMBA Sport 21 Hydro 1 mi. racing record - 88.79 sec.

IMPBA 21 Mono 1/3 mi. Oval - 26.49 sec. 45.29 mph.

IMPBA US-1 Champion

NAMBA National Champion

Use Brown 21 parabolic pipe set at 8.0" (cylinder center to weld).

Use with MAC 14mm ( large O.D.) header.

Head clearance - .008"

Nitro - 60%
Parts & Price List
CLICK HERE to open our price list for the MAC 21 engine, and components.

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Mac 21 | Mac 45 | Mac 67 | Mac 84

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