This is a 10-piece Race Head Gaskets Bundle for 1991 to 2005 Mercury 2.5 Liter 2-stroke outboards.
 
This kit has been assembled from 3 of the world's top outboard head gasket manufacturers to provide a kit to tune your compression without having to change your heads. 
 
This kit is a must for 1) outboard drag racers (SODA, ODBA, DSRA, UMPBA) running a maximum compression rule class, 2) outboard tunnel boat racers (APBA, OPC, F1H20, AFPGP) with minimum squish rules, 3) other high-performance boats and tuners looking for optimal 2-stroke engine performance. 
 
The kit includes the following head gaskets:
 
2 x 0.75mm (0.0295" thickness)
2 x 1.00mm (0.0393" thickness) 
2 x 1.10mm (0.0433" thickness)
4 x 1.20mm (0.0472" thickness)
 
These outboard AFM cylinder head gasket fits all 1991 - 2005 gasket-head 2.5 liter 2-stroke Mercury / Mariner 135, 150, 175, 200, 225 Pro Max, 260 ROS, 300 Drag, XR6, and Sportjet 175 HP powerheads.
 
Part Numbers:
18-3864, 184721, 35870, 822844, 822844T04, 822844T05, 822844004, 8228441, 8228442, 8228443, 9-63854, 9-63854, 8228441, 814658-1 0.75, 822844-1 1.00, 27-840322-1 1.50 (.060)
 
Contact mike@buckshotracing77.com with any questions 714-697-1716
 
Head Gasket Thickness & Suggested Clearence
 
0.75mm (0.0295" thickness) is suggested for pistons at .008" (or more) below deck height
 
1.00mm (0.0393" thickness) is suggested for pistons at .000" (or more) below deck height
 
1.10mm (0.0433" thickness) is suggested for pistons at .004" (or less) over deck height
 
1.20mm (0.0472" thickness) is suggested for pistons at .008" (or less) over deck height
 
1.50MM (0.0591" thickness) is suggested for pistons at .020" (or less) over deck height
 
Racer who have explored the limits may be able to run tighter squish clearances.