BOX STOCK RULES

1. This is a BOX STOCK class. Stock 5HP Briggs as supplied by the manufacturer. With all OEM parts. Overbore of .035 Raptor 3 Piston allowed.

2. Fuel, any pump gas. No racing gas or any additives.

3. Oil, any type oil may be used. No additives.

4. Camshaft must be stock Briggs cam with broch marks visible. No ground cams.

5. Carb, stock Briggs carb #397135 or #555129 are allowed. Carb cannot be altered in any manner. Holes left in carb after choke removal must be plugged and plugging cannot protrude into air horn area. Metering holes CANNOT be touched. Stock jet must be used and may be .034-.039 hole size allowed. The slide choke style carb not allowed. No drilling of holes anywhere in carb. Diaphram and spring installed as supplied from factory. Cover plate cannot be touched. Pick-up tubes must remain stock, screens may be on or off. Felt or foam washer must be on throttle shaft. Stop arm on shaft not tech item. Remainder of throttle shaft must remain unaltered. No reworking to enhance performance allowed.

6. Timing, Stock unaltered flywheel (6 lb. 4 oz.minimum) weight with stock flywheel timing key in place and unaltered. Camshaft and crankshaft timing marks must be lined up.

7. Heads, stock as shipped from factory, no machining, polishing. HEADS ARE TO REMAIN UNTOUCHED.

8. Piston, stock OEM only may use up to .035 Raptor 3 piston.

9. Rods, stock no undersizes, nylon dippers allowed. No billet rods allowed.

10. Crankshaft, stock OEM, no undersize allowed, may be clearanced to minimum .775 for bearing removal.

11. Valves, must be stock Briggs valves.

12. Springs/Lifters, Stock as shipped from factory.

13. Blocks, No machine work or porting allowed, cannot be touched except to bore cylinder.

14. Piston/Deck Clearance must not exceed .005 pop-up above top of the block.

15. Valve breather must be stock.

16. Gaskets, Head gasket must be stock Briggs no less than .043 thick. Other gaskets can be stock or aftermarket but must be of same size and material as stock gaskets.

17. Ignition, stock Briggs coil must pass Ohms tests min. 2000 max. 5000 ohms.

18. Air filter, WKA approved aftermarket filter adaptor and filters allowed.

19. Headers, any header with WKA approved muffler allowed.

20. Clutch: Noram, Magnum, Ratech type only drum style - NO disc clutch allowed.

21. Weight: 345 pounds Age: At least 12 years old.