2017 rules given to NASCAR teams

Motorsport.com has obtained a copy of the proposed modifications for next season. Some of the highlights include:
1. Testing policy – An update to the National Series testing policy which would allow drivers returning to the sport following a medical absence to have an extra test under the discretion of the sanctioning body.
2. Spoiler Size – For non-superspeedway events, the spoiler height will be reduced from 3.5 inches to 2.375 inches, further reducing downforce.
3. Mandatory Roof Hatches at Superspeedways – Roof hatches will remain optional at other race tracks.
4. Energy Absorbing Material added to the toe board in the driver's cockpit – NASCAR-approved toe board will be mandatory at Superspeedways.
5. Frame Changes – In an effort to restrict movement of the rear axle during competition, NASCAR is mandating change to the main frame assembly, truck trailing arm crossmember assembly, track bar mount and truck trailing arm on rear suspension, arm spacer and pinion angle shim.
6. Restrictor Plates – For superspeedways, the initial restrictor plate hole size will decrease from 57/64 to 7/8 inch.
See more at Motorsport.