SPORTSMAN/LIMITED IRON FORD ENGINE RULES
Engine set back is a maximum of six inches (6") from center of ball joint to front of most forward spark plug hole.
HEADS
1.Sportsman M-6049-N351 or M6049-N352 heads allowed. NO after market heads. N351 head maximum intake runner volume
195CC, Exhaust runners 80CC maximum. N352 head maximum intake runner volume 188CC, and Maximum exhaust runner
volume 77CC. Combustion chamber volume either head, 62CC. NO Tolerance. Maximum valve size 2.02” intake, & 1.65”
exhaust.
2.Cylinder head must be un-ported. NO porting, polishing, gasket matching, or coating on inside of head runners. No Epoxing in
runners. No short side radiousing.
Must be able to see and feel the defined raised lip of original bowl in the cylinder head, in all areas of the bowl, AND All bowl work
must
Remain concentric with the valve guide, and NO machined or grinding work more than .650” below the 45 degree valve seat. Any
Work done more than .650” below valve seat will be deemed port work NOT part of the valve job. Any completely smooth blends,
of the bowl on the short side (even though you can see where the cutter stops) will be considered short siding, again must be
able to
see and feel the defined raised lip of the original bowl.
3.Stud mount rockers ONLY, stud must go through center of rocker arm. No shaft mount rockers.
BLOCK
1.M6010-D351, M351, or N351 are acceptable blocks. N351 block will cost the racer the least amount money on machine work,
and would be preferred.
2. Dart Block Part #31384195, and 31385195 allowed. World Products Block part # 087150 and 087152 allowed.
3. No lightening of engine blocks allowed.
CRANKSHAFT
1.Any cast or forged steel (No Billets) crankshaft must have a stock stroke of 3.50”, and weigh a minimum of 54lb. No knife
edging or winging of cranks. Ford part #M-6303-G351 is a good place to start, The M-6303-G351 is to lite.
2. Ford may run after market crankshaft, but must meet all of above criteria.
OIL PUMP
1.Wet sump oil system, or may use an external single stage belt driven oil pump. Oil must be pumped from, and returned to oil
pan.
CONNECTING RODS
1.Any forged steel “I Beam” sportsman style rod. Maximum rod length 6.00”. No profiling of rods, no cnc maching of center of
beam, no removing of manufacture name and rod size.
2.Minimum Rod pin diameter 2.00”
3. Eagle H-Beam or Callies “Compustar” H-beam rods permitted. These are ONLY H-Beam rods allowed
PISTONS
1.Any flat top piston.
ENGINE BALANCING
1.Engine Balancing permitted
CAMSHAFT
1.Any flat tappet cam
2.Stock diameter lifters ONLY ..875”, OEM size to make of engine, NO ceramic foot lifters allowed, all lifters must have a magnetic
base.
3.NO roller cams or lifters
4.Cast iron stick ONLY, NO billet cams.
TIMING GEARS
1.Timing chain and gears ONLY
2.NO gear drives, or belt drives
INTAKE MANIFOLD
1.Any cast iron or aluminum intake.
2.No porting, polishing, squaring/gasket matching of ports.
3.May run 1” spacer
4.Turtle OK not altered
5.Total adapter not to exceed 1” total. Any thing mounted between carburetor and intake is considered spacer, and can not
exceed 1” total.
6.Directional spacers OK.
7.All intakes must be from a recognized name brand intake manufacturer, ex Edelbrock, Brodix, Holley, Weiand, etc. MUST have
manufacturers name and part number intact and unaltered. NO import manifolds allowed
CARBURETOR
1.One dual line, single pump 3310 Holly, with Vacuum sec.
2.May remove choke butterfly.
3.May drill idle holes in primary butterflies. There should be No half, or flat throttle shafts in the primary side of the carburetor’s
base plate.
1.The primary throttle shaft, with a 172 butterfly should be a minimum of .1868” thick
2.The secondary round shaft, with a 172 butterfly should be a minimum of .1828” thick.
3.The secondary half or flat shaft with a 172 butterfly, should be a minimum of .1228 thick
4.Billett base plate allowed must meet factory Holly specs. On throttle bores, and above throttle shaft specs.
Note: Checked with go-no-go gauges
4.May install secondary jet metering plate, Billet metering plate allowed.
5.May NOT remove choke horn.
6.NO porting or polishing.
7.Ford 735 c.f.m. OK, Secondary Throttle screw OK.
8.Single pump ONLY. No rear nozzles.
9.Four corner idle OK.
10.Carbs checked with Go-No-Go gauges.
11.stock inside diameter boosters 3310 Holley. Down leg Boosters OK, must remain stock Holly specs.
FUEL PUMP AND FUEL CELL
1.Stock mount fuel pumps ONLY.
2.No electric or belt driven fuel pumps
3.Steel case on fuel cell recommended
WATER PUMP
1.Stock mount ONLY.
2.Electric fans OK.
IGNITION
1.Any battery operated.
2.No crank trigger ignition, & No Magnetos
3.NO Electronic Traction Control device!!
4. MSD Boxes may not be mounted in drivers cockpit. The trigger wiring Harness (ie. green and purple wires) must go straight
from box thru firewall and follow along engine side of firewall, and be easily accessible for inspection.
RADIATOR
1.Must be close to stock location, mounted in front the motor.
STARTER
1.Must have operating starter.