Reply To: BRIGGS MODIFIED CLASS

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#50247
Angie MacEwen
Participant

This was the initial set of rules that Greg provided. Work on something more official was stopped, so this may be it. Just to be clear, this class will not run unless we have 6 people sign up for memberships with the intention of running it.

Engines:
Briggs & Stratton Animal Modified
World Formula Modified

Fuel: Methanol
Weight: 350lbs.

Note: ***All parts must be Briggs & Stratton Stock factory production parts. NO machining or alteration unless specified in these rules. If it is not in the rules, it MUST REMAIN STOCK***

FLYWHEEL: B&S part #555625 is the ONLY billet flywheel permitted. Any or no flywheel key allowed.
CARBURETOR: Any Tilletson HL series carb. Max throttle bore 1.005? / Max venturi .900?.
INTAKE: Any intake allowed.
AIR FILTER: Any filter allowed.
FUEL PUMP: Any pulse type pump allowed. Can be pulsed from intake or crankcase.
ROCKER ARMS: Must be stock as from the factory. Length?2.880?+/- .005?
LIFTERS: Billet allowed
HEADER: Any header allowed
CONNECTING ROD: ONLY Billet rods allowed. With or without inserts. Must be stock length.
PISTON AND RINGS: Any aftermarket piston and rings allowed. Three rings mandatory.
CRANKCASE SIDE COVER: Billet allowed.
CRANKSHAFT: ONLY stock factory crankshaft with stock timing gear allowed.
CAMSHAFT: Max. lift .310? Max duration at 0.050? 248 degrees. Max. duration at 0.200 – 153 degrees.
CYLINDER HEAD: Machining of gasket surface allowed.
VALVES: Stock valves ONLY. One angle.
VALVE SEATS: Stock seats ONLY. One angle
HEAD GASKET: Min. thickness .049?
VALVE SPRINGS: Any springs allowed.
DECK / PISTON CLEARANCE: Machining of deck surface allowed. Piston pop-up is non-tech.
CYLINDER BORE: .035? over max
BLOWER HOUSING: B&S part #555623 or #557034. Heavy flywheel cover ONLY.
THIRD BEARING SUPPORT / GIRDLE: allowed
ROCKER STUDS: can be girdled together. Stock studs ONLY..
CHASSIS: NO Cadet Chassis allowed.