20F- 4 GENERAL ENGINE REQUIREMENTS - Engine must be OEM cast
iron V8 production block #10066034 or equal to. No aftermarket or bow tie blocks.
The only approved engine for GM is the CHEVROLET 350, the maximum
decking of the block is 9". No angle milling of block deck.
No offset dowel pins. No de-flashing, grinding, welding, or painting of any
internal area. Maximum overbore is .045". A max static compression ratio of
10 to 1 will be allowed .
20F- 5 DETAILED ENGINE REQUIREMENTS - All
parts for this spec engine must maintain manufacturers’ overall dimensions and
weight with no exceptions! The approved part numbers are as follows:
GM BLOCK - #10066034
PISTIONS- Wiseco Pro Tru- #PT003H
- JE SPR- #157076 - Manley-#59053
Rods- Manley-14104-8 - Crower
Sports Rods- sp3205
Oil pan - Moroso-#12312 -
Canton-11-122
Valves - Manley Intake #11596
& #11864 - Manley Exhaust #11543 & #11863
Crank- Scat Cast or Steel -
#9-350-3480-5700 & Callies Magnum Series
Intake-Edelbrock #2101
Harmonic Balancers- Pro Product
Powerforce Plus #90010 & Power Bond #PB 1012-SS
Carburetor Spacers- #85-060 &
#85-065
20F- 5.1 ENGINE
LOCATION
A.
Engine must be in the stock location for a V8 in the chassis being run. Stock
engine location is deemed to be when the distance between centerlines of the
forward most fuel pump to engine block mounting bolt and the upper idler-arm to
frame mounting bolt measures 8.75” +/- .25” inch so long as said bolts are
deemed to be in stock, un-altered, factory locations.
B. The front, centerline of the
crankshaft must be no less than 12.75” from the ground with the car’s frame set
on five (5”) inch high blocks under all four outer corners of the frame.
Compression
rings 1/16”
Oil ring assembly 3/16”
B. Only magnetic steel piston pins
maintaining a minimum diameter of .0927” are permitted. Full floating
pins are permitted.
C. Piston pin holes must be in a fixed
location in the piston and connecting rods.
D. Only two-piece insert style
connecting rod bearings are permitted.
E. The only solid magnetic steel stock type connecting rods that
are permitted will be the Manley # 14101-8 and the Crower Sports Rod # SP3205. Hollow beam connecting rods are
not permitted. Only normal engine
balancing and the use of after-market bolts and nuts are permitted. No
de-burring, de-flashing, polishing, grinding or lightening. Billet connecting
rods are not permitted. The only rod length permitted will be 5.7”.
F. Titanium and stainless steel connecting rods are not
permitted.
G. Minimum weight for piston, pin, ring, bearing and rod assembly
is 1185 grams.
20F- 5.5.4 OIL PAN - NO dry sumps,
external oil pumps or tanks or accu-sump systems allowed. The only oil pans
that will be permitted are the MOROSO #12312 and the Canton #11-122. Oil coolers are
allowed. Only OEM in the pan magnetic steel type oil pumps are permitted. No
pumps of any type may be used in the evacuation systems.
20F-5.6 HEADS - CAST IRON. The only CHEVROLET head allowed
will be the DART casting part # 10024266. Angle plug,
Bow-tie or Vortec heads are not permitted. Intake valve must be 2.02" only. Exhaust valve must be 1.60"
only. The head must have a minimum of 65cc combustion
chambers. When heads are checked at the track you will be responsible for
cleaning and carbon removal to make the respective cc limit. The only
modifications ALLOWED will be the installation of valve guide sleeves and
milling of the gasket surfaces. Milling of Exhaust flanges, angle milling,
changing the angle of the head gasket surface in relationship to the rest of
the head, altering the position or angle of the valve guide is not permitted.
The addition of screw-in studs, guide plates, valve spring seats, optional
valve seals, Poly-Locks or jam-nut devises are permitted. The only machining of
valve guide bosses allowed, is for seals only. Coolant return lines are allowed
to be placed on the ends of the heads. No lines will be allowed on the sides of
the head. Other head modifications that
are not permitted include but are not limited to: Porting, polishing, any
grinding in ports or combustion chambers, chemical milling, glass beading or
removal of any flashing or casting marks. No welding or sectioning. No internal
modifications of any kind including painting or Teflon coating. No more than
two intake-mounting holes may have HeliCoils. Intake or exhaust manifold
mounting holes may not be added or relocated. Holes must take standard intake
manifold bolts. All external dimensions must remain as provided by the
manufacturer .
A. All heads will be subject to
max port volumes. Max Intake volume will be 177cc. The max Exhaust port volume
will be 71cc.
VALVES - The only valves that are
permitted will be the Manley valves, Intake # 11596 @ 111
grams, Intake # 11864 @ 114 grams. Exhaust # 11543 @ 95
grams, and Exhaust valve # 11863 @ 102 grams. No air
directional devices will be permitted on any of the valve surfaces. Valve stems
must have a minimum diameter of 11/32 inch. Valve
lifters can weigh no less than 85 grams. All parts must
maintain production grams!
VALVE JOB - When cutting the
valve seat angles, no stone or grinding marks are permitted above the bottom of
the valve guide. All cutting in reference to the valve job must be centered off
the centerline of the valve guide. Upon completion of the valve job, the bowl
area under the valve seat down to the bottom of the valve guide should still be
the same configuration as far as shape and finish as it was from the
manufacturer. The bowl area must pass the “ball” check. Intake must pass a .787 ball. The exhaust
must pass a .531 ball. These ball sizes must not be able to pass through the
bowl area. Surfaces and/or
edges where the cutter or stone has touched must not be polished. No hand
grinding or polishing is permitted on any part of the head.
VALVE SPRINGS & RETAINERS - The only
steel retainers allowed will be of a weight no lighter than 30 grams. No barrel wound, conical wound springs, or
beehive type springs will be allowed. ALL windings must be parallel. Valve
spring retainers must be OEM steel or stock or stock replacement steel only. Double
valve springs with a max diameter of 1.450” and a minimum diameter of 1.437”
will be allowed. Valve springs must have a height of
1.750” min to 1.800” max. No lightweight retainers will be allowed. The only locks that will be allowed will
be the Machine 7 degree, Super 7 degree, and the 10 degree
magnetic steel only!
B. Small journal, or Honda
pin crankshafts will NOT be permitted.
C. NO machining or polishing of the crankshaft counterweights allowed.
NORMAL engine balancing will be the ONLY acceptable modification that can be
performed on this component. No painting or Teflon coating. No capping of the
counterweight holes. Crankshafts must maintain the manufacturers’ appearance.
D. Minimum
crankshaft weight will be 48 lbs.
E. The Only OEM magnetic steel elastomer type harmonic balancers
will be the Pro Product Power Force Plus #90010 or the Power
Bond # PB1012-SS only.
20E-
5.8.1 CAMSHAFT - Only magnetic steel camshafts will be permitted. The
maximum camshaft bearing journal size must not be more that 1.875" (475mm).
Camshaft must not exceed .550 lift at the valve with zero lash.
A. ANY type chain will be
permitted. Belt-drive and gear-drive systems will not be permitted.
B. Only
production sleeve type bearings will be permitted and must be standard diameter
for the production block being used. Needle bearings will not be permitted.
C. Camshafts must be driven in the same direction of
rotation as that of the approved production engine.
E. Solid cam
and lifters may be used.
A.
.842” diameter magnetic solid steel valve lifter
will be the only diameter permitted. Roller tappets, ceramic valve lifters,
mushroom valve lifters and any type of mechanical assistance exerting a force
to assist in closing the valve and/or push rod commonly known as rev-kits will
not be permitted.
B. Valve lifters can weigh no less
than 85 grams.
20F- 5.8.3 ROCKER ARMS - Aluminum or
stainless stud mounted roller rocker arms are permitted. 7/16” studs may be
used. Steel 5/16” x .080” wall
push rods must be used. Chevrolet must run 1.5 ratio rockers. No
stud-girdles. No aftermarket shaft rocker systems.
20F- 5.9 INTAKE MANIFOLD - The only Intake manifold that will be allowed
will be the Edelbrock #2101. You are required to have an UNALTERED manifold. NO porting,
polishing, acid dipping, deburring, de-flashing, abrasive cleaning, internal
painting, milling, cutting, drilling holes, enlarging bolt holes, matching of
ports or welding. Absolutely no modifications of any kind. A track supplied
stock intake manifold must fit your engine complete with stock gaskets. All
bolt holes must be in alignment and same size as stock. Absolutely no coolant
lines in the intake manifold, engine block, or sides of heads.
1.The Intake to pin measurement must be
no less than 6.050”, no exceptions !
2.The maximum thickness aloud for the
Intake gasket will be .064”, no exceptions !
20F- 5.10.2 CARBURETOR SPACER - The approved spacers for this motor will
be the Canton # 85-065 or the # 85-060 with a maximum
height of 1” permitted with the only exception being .075" max. gasket per
side. No wedge shaped mounting surfaces, both top and bottom surfaces must be
parallel. Port holes, or hole, must be
vertical to the surface with no beveling, tapering, or flaring. No additional
openings for the induction of air allowed. All spacers must be approved by
Track Officials.
20E- 15 FUEL SPECIFICATIONS - The
only approved fuel will be the 260 GTX no exceptions!
A. Icing or cooling of the fuel system
is not permitted in the garage, pit or racing area.
B. Gasoline may be tested and certified
at any event through the application of various chemical analyses as considered
appropriate by officials. Gasoline may be checked before, during and after the
racing events.
C. Nothing may be placed in the fuel line other than a standard
fuel filter. The use of any type of fuel catalyst or other fuel-altering
devices is prohibited.
The only approved labor will be
as follows:
Bore & hone block w/plates
.045 over.
Cut flats of block.
Deck block 9” max.
Prep block
line hone block
Boil cam bearings and plugs
Balance engine /normal no capping of holes
Fit 8 rods and side clearance
Hang 8 pistons and pin fit
Clean and polish crank shaft
Touch seats on new heads
Cut 4 sides 0f new heads/NO ANGLE
MILLING
cutting for valve seals &
spring pockets will be permitted
Fit 16 guides
No other labor will be allowed!
The only
procedure that will be grandfathered in at this point & time will be
SLEEVES FOR THE LIFTER BORES in the old blocks. IF YOU ARE USING A NEW BLOCK
AND WANT TO INSTALL LIFTER BORES, IT WILL INCREASE THE TOTAL COST BY A FEW
HUNDRED DOLLARS.
These SMS SPEC MOTOR rules are intended to create a standardized rule
package to cut costs and increase the level of competition. If these rules are
not followed as written above, Stafford
reserves the right to determine stiffer forms of penalties then we have in the
past. THIS RULE IS STILL UNDER REVIEW BY STAFFORD SPEEDWAY!