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This page updated on
February 28, 2008

For a complete ULRS Rule book,
please contact Cindy Moore at the ULRS.

We started with the "important" stuff ...

20. HULL and ENGINE SPECIFICATIONS

There will be five options for hull and engine specifications allowed to compete in the UL class.

OPTION ONE:

(A) Hull minimum weight in racing trim, without driver, shall be 2,000 pounds.

(B) ENGINE

1) U.S. Manufacturer, automotive or marine, four cycle, internal combustion type.
2) Total cubic inches not to exceed 468.
3) Engine must be normally aspirated utilizing any American-made 600 CFM carburetor with a throttle bore as follows:

a) Primary 1-9/16" max.
b) Secondary 1-9/16" max.
c) A .250 inch thick restrictor plate, located a maximum distance of 1.50 inches directly beneath the carburetor, with these dimensions, will be acceptable.

4) Ignition may be any type, except for crank-driven type.
5) No overhead camshafts
6) Maximum two valves per cylinder.
7) Cast intake manifolds only. Must be available from a major manufacturer. Plenums and spacers may be fabricated.
8) No nitrous oxide or other power producing additives.

Option One A - Alternate Engine

The following is the alternate 468 CID engine that is allowed:

1) 468 CID with only one of two bore, stroke combinations allowed.
2) Stock length rods, 6.135 in.
3) Carburetor: Holley 4 barrel carburetor with throttle bore 2 inch max.
4) Cylinder heads: Only Chevrolet commonwall intact cylinder heads allowed.
No Brodix-Dart-Pontiacs, etc.
5) Valves: Intake 2.19 diameter max. Exhaust 1.88 diameter max.
6) No grinding or polishing of any kind in the intake ports, exhaust ports, or combustion chambers.
7) Cast intake manifolds only. Must be available from a major manufacturer. Plenums and spacers may be fabricated.
8) Only stock 1.7: 1 rocker arm ratio
9) The bore and stroke combinations allowed will be 4.310 x 4.00 or 4.440 x 3.760.
10) No nitrous oxide or other power producing additives.

OPTION TWO

(A) Hull minimum weight in racing trim, without driver, shall be 2,500 pounds

(B) ENGINE

1) U.S. Manufacturer, automotive or marine, 4 cycle internal combustion type.
2) Total cubic inches not to exceed 511.
3) Engine must be normally aspirated utilizing any American-made carburetor with a throttle bore as follows:

a) Primary 2" max.
b) Secondary 2" max.
c) A .250 inch thick restrictor plate, located a maximum distance of 1.50 inches directly beneath the carburetor, with these dimensions, will be acceptable.

4) Ignition may be any type, except for crank-driven type.
5) No overhead camshafts
6) Maximum two valves per cylinder
7) Cast intake manifolds only. Must be available from a major Manufacturer. Plenums and spacers may be fabricated.
8) No symmetrical port heads (Chrysler Hemi and Ford excepted)

a) Allowed: Common wall type including Chevrolet, Dart 320 & 360, Brodix -1, -2, -3, -4, B1-TS Dodge and other non-symmetrical port cylinder heads.

b) Not allowed: Pontiac Prostock, Dart Big Chief, Olds DRCE, Dart Oldsmobile, Brodix EPD, Dodge B1-TS and other symmetrical port cylinder heads. If in doubt, contact the UL technical advisor.

9) Determination on the permitted use of any cylinder head shall be solely the responsibility of the UL technical advisor.
10) No nitrous oxide or other power producing additives.

OPTION THREE

(A) Hull minimum weight in racing trim, without driver, shall be 2,000 pounds.

(B) ENGINE

1) U.S. Manufacturer, cast iron block, automotive or marine, 4 cycle, internal combustion type.
2) Total cubic inches not to exceed 468.
3) Engine must be normally aspirated utilizing any American-made carburetor with a throttle bore as follows:

a) Primary 2" max.
b) Secondary 2" max.
c) A .250 inch thick restrictor plate, located a maximum distance of 1.50 inches directly beneath the carburetor, with these dimensions, will be acceptable.

4) Ignition may be any type, except for crank-driven type.
5) No overhead camshafts.
6) Maximum two valves per cylinder
7) Cast intake manifolds only. Must be available from a major Manufacturer. Plenums and spacers may be fabricated.
8) No symmetrical port heads (Chrysler Hemi and Ford excepted)

a) Allowed: Common wall type including Chevrolet, Dart 320 & 360, Brodix -1, -2, -3, -4, B1-BS Dodge and other non-symmetrical port cylinder heads.

b) Not allowed: Pontiac Prostock, Dart Big Chief, Olds DRCE, Dart Oldsmobile, Brodix EPD, Dodge B1-TS and other symmetrical port cylinder heads. If in doubt, contact the UL technical advisor.

9) Determination on the permitted use of any cylinder head shall be solely the responsibility of the UL technical advisor.
10) No nitrous oxide or other power producing additives.

OPTION FOUR

A) Hull minimum weight in racing trim, without driver, shall be 2,500 pounds.

B) ENGINE

1) U.S. Manufacturer, automotive or marine, four cycle, internal combustion type.
2) Total cubic inches not to exceed 511.
3) Engine must be normally aspirated utilizing a Holley four barrel carburetor with throttle bore as follows:

a) Primary 1 9/16" max.
b) Secondary 1 9/16" max.
c) A .250 inch thick restrictor plate, located a maximum distance of 1.50 inches directly beneath the carburetor, with these dimensions, will be acceptable.

4) Ignition may be any type, except for crank-driven type.
5) No overhead camshafts
6) Maximum two valves per cylinder
7) Cast intake manifolds only. Must be available from a major Manufacturer. Plenums and spacers may be fabricated.
8) No nitrous oxide or other power producing additives
9) No cylinder head restrictions.

OPTION FIVE

A) Hull minimum weight in racing trim, without driver, shall be 2,500 pounds.

B) ENGINE

1) U.S. Manufacturer, automotive or marine, four cycle, internal combustion type.
2) Total cubic inches not to exceed 468.
3) Engine must be normally aspirated utilizing a Holley four barrel carburetor with throttle bore as follows:

a) Primary 2" max.
b) Secondary 2" max.
c) A .250 inch thick restrictor plate, located a maximum distance of 1.50 inches directly beneath the carburetor, with these dimensions, will be acceptable.

4) Ignition may be any type, except for crank-driven type.
5) No overhead camshafts
6) Maximum two valves per cylinder
7) Cast intake manifolds only. Must be available from a major Manufacturer. Plenums and spacers may be fabricated.
8) No nitrous oxide or other power producing additives
9) No cylinder head restrictions.

OPTIONS TWO, through FIVE SPECIFICATIONS, MAY BE CHANGED BY THE ULRS TECHNICAL INSPECTOR, WITH APPROVAL BY THE ULRS CHAIR, TO ACHIEVE PARITY WITHIN THE CLASS.

The specifications which may be changed are limited to boat weight and the size of the throttle bore permitted.