which one is better to build?
what are some cheap upgrades to make more power?
here are the rules
MODIFIED MOWER CLASS RULES
1) Engines:
a) 5 to 20 horsepower single or twin cylinder.
b) Vertical or horizontal shaft.
c) Must be lawn mower type engine
d) May be internally and externally modified.
e) Must use stock steel flywheel no aluminum flywheels allowed in this class.
f) Must be 4 cycle engine.
g) Exhaust must route downward or to the side of the mower. Must be stock muffler in good working condition. Maximum decibel limit of 62
2) Transmission/Drive-line:
a) Driveline choice is open. (Gearboxes, centrifugal clutches, torque converter clutches direct drives, solid rear axles)
3) Body and Frame:
a) Must have a lawn mower frame. If stock frame is inadequate for racing, it may be reinforced or a new one built from steel of the same dimensions and style. No aluminum frames.
b) Wheel base may be no longer than 60 inches (that’s the length from axle to axle)
c) Width may be no wider than 42 inches (that’s outside tire to outside tire distance)
d) Body must have lawn mower style hood and fenders. May be modified to fit frame. Hood must be locked down in place securely.
4) Starters:
a) Electric or pull start only. No hand held gear drive starters (like on go-karts and dragsters)
5) Gas tanks and fuel systems:
a) Gas tanks must be securely mounted and reasonably protected. (NO nitrous oxide allowed)
b) Inline fuel shut off valve mandatory.
c) No fueling a running engine.
6) Throttles:
a) Any type throttle may be used, twist grip, thumb throttle, squeeze grip or foot pedal. Must operate freely and have an operable return spring. No fixed throttles.
7) Safety Kill Switch:
a) Tether switch is mandatory. Mowers must have breakaway type. Similar to types found on boats, wave runners, quad runners. The hook-up cord may be no longer than 30 inches stretched out. It may not reach any further than the back of the driver’s seat.
Wheels and tires:
a) Any style wheels may be used. They must be mounted securely to the axle.
b) 4Turf style tires only (No slick tires are allowed). Tubes must be used in front tires.
9) Brakes:
a) Mandatory! Brakes must be upgraded from stock braking system.
10) Suspension:
a) Steering arms and tie-rods ends must be 3/8 inch diameter minimum.
b) Must use heim joints or large type ball joints.
c) No shocks or springs are allowed.
11) Bumpers/Safety Bars/ Mower Decks:
a) Front bumpers are MANDATORY, may not exceed the front width of the tires.
b) Rear bumpers must not exceed the rear tire width.
c) Running boards or nerf bars are highly recommended but can NOT exceed the width of the tires. Mowing decks may be used in place of running boards or nerf bars, but must be securely fastened to the fame of the mower. An outside barrier on the running boards or mowing deck to keep your feet from slipping is highly recommended (will help control your body weight while cornering).
d) Center of bumper should be 10 inches off the ground and 6 inches in height.