Afton Motorsports Park Modified Engine Rules
The Modified engine rules for Afton Motorsports Park are listed on this page.
MODIFIED ENGINE - Page 1
[BIG BLOCK-BIG SMALL BLOCK (OVER 358 CD) ENGINE SPECIFICATIONS] [Engine] [Carburetor] [Intake Manifold] [Cylinder Heads] [Camshaft] [Pistons / Rods / Crankshaft] [Ignition] [Lubrication] [Fuel]
Page 2 of Rules: [Go to Page 2] Includes 358 Modified Engine Specifications: Engine, Blocks, Cylinder Heads, Crankshaft, Rods, Pistons, Vibration Dampners, Camshaft, Intake Manifold, Carburetor, Ignition, Lubrication System and Fuel
[PDF of Modified Engine Rules] [Download Adobe Acrobat]
(Afton Motorsports Park allows various engine combinations. This is a guideline for the more popular).
- Any cast iron block.
- Only normally aspirated engines are permitted.
- Maximum displacement of 467 cu.
- No reverse rotation engines.
- 1 - 4 barrel carb.
- Optional as to design or manufacturer, but the manifold must allow for the mounting of only one 4 barrel carburetor.
- Any 2 valve per cylinder head.
- Optional as to design or manufacturer but must be made of cast aluminum or cast iron only.
- Valve sizes are optional.
- Any form of porting is permitted.
- Titanium valves and retainers are permitted.
- No hollow stem valves or liquid cooled valves are permitted.
- Only 2 valves per cylinder are permitted.
- Only one spark plug per cylinder.
- Optional as to design or manufacturer but camshaft must be in block in stock location.
- No overhead cams are permitted.
- Any 3 ring piston, any steel rod/crankshaft - no titanium.
- Any kind of ignition is permitted, as long as it is mechanically driven in the stock position.
- No crank trigger ignition systems are permitted.
- Only one ignition coil and one ignition box (amplifier) are permitted on the car.
- Only one spark plug per cylinder is permitted.
- Traction control devices are not permitted. Traction control devises that use the brakes are also illegal.
- Ignition boxes must remain as manufactured with no internal or external alterations. NOTE: Ignition boxes may be swapped or confiscated by Speedway at any time.
- Conventional or dry sump may be used.
- Only racing fuel or pump gas is permitted - small block under .360 C.I. can run alcohol.
- No nitrous or any other additives are permitted.
- All fuels are subject to random testing at each track.
- No electric fuel pumps are permitted.