Caged Stock Animal Rules

Gold Plate &  Stock Animal Class Rules


Cylinder blocks: (max. .030 bore) (piston pop up +.005" MAX).

Converted Inteks must run Animal head

Piston: stock Briggs pistons installed per. Manufacturers specs. (Arrow to mag. side, no machining)

Rings: Three rings are Mandatory.  O marking must face up on 1st and 2nd ring.  Oil ring must be installed as from factory. Rings must be self supporting in cylinder bore.

Rod: Any stock length rod can be used.

Crankshaft: Stock crank. (Stock dimensions)

Flywheel: Stock Jr. Racecar or Briggs PVL. (Stock magneto)

Cylinder head: Combustion chamber floor depth, no less than .319!

Combustion chamber squish band areas around plug and bottom portion of chamber no less than .011! (Will be measured with a quality depth gauge and will have 0 tolerances.)

Valves:  Intake OD min. & max. 1.055 - 1.065, Exhaust OD min. & max. 935 - .945  Minimum Valve Length = 3.250"  (1 angle, no polishing, stock keeper grove location)

Valve springs: Stock valve springs. (Or stock replacement to exact stock specs)

Camshafts: will be profiled out using a degree wheel with IKF profile. (Maximum cam lifts .257") (Gross valve lift will be teched @ valve spring retainer .255" maximum lift with no lash) ( Factory core camshafts only)

Lifters: stock replacement only.

Push Rods: Stock length. (5.638-5.656 minimum and maximum length)

Rocker Arms: Stock replacement only. (No alterations of any kind, comparison to a known stock part will be used)

Valve Cover: Stock valve cover with working stock baffle. No tapping or welding.

Carburetor: Items that drop from the bottom of carburetor with bowl off are not tech items:

Examples: main jet, pilot jet, float, needle and seat, emulsion tube.

Intake manifold: The only alteration allowed is slotting of holes for proper alignment.

Restrictor plate: Plates may not be altered in any way.  No beveling of holes, either side.  Plates will be checked with no-go gauge.  Plates must be installed with tab on the right side.

Fuel pump pulse line: (top oil fill on side cover is the only allowed place)

Crank case ventilation: (from valve cover only)

Starter: Any type starter allowed.

Notes: These engine tech specs can be changed at any time per tracks updates.

All engine parts, except listed allowed changeable parts can be teched to a known stock Briggs Animal part.

Notes: This is a stock engine class and if anything is altered or replaced other than what is listed in this engine spec sheet it does not fit the mandated requirements.  All Animal engines will be teched per IKF go/no-go gauges.

Gold Plate Animal (Gas or Alcohol) 315lbs. / 8-11 Years of Age

1. This is a Restricted IKF/WKA Briggs & Stratton Animal class.  The only approved motor is the Briggs Animal OHV.

2. Must run  3-hole .312” Gold Horstman restrictor plate.  Will be teched with .314" no/go.  Restrictor must be mounted between Carburetor and Manifold.  Restrictor may not be altered in any way.  Must use gasket between restrictor and manifold.

3. May use any clutch (disc or drum)

Caged Stock Animal (Gas or Alcohol) - 330lbs. /  10 to 16 Years of Age

1. This is a IKF/WKA Briggs & Stratton Animal Class.   The only approved motor is the Briggs Animal OHV.

2. May use any clutch (disc or drum)

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