MANUFACTURERS' GUIDANCE INDEX FOR 1981 LETTERS DATE TO: SUBJECT: 1-23-81 LD Summary/Assessment of 1981 Model Year Abbreviated Certification Review Program (not legible, not scanned - re-typed) 3-24-81 "SF" Multigrade Fuel-Efficient Engine Oils 4-02-81 LD/HD Choke Vacuum Breaks--Parameter Adjustment Regulations 6-04-81 LD Test Fuel Temperature for Precondi- tioning 7-01-81 Relief for Manufacturers--Certification Program Policy Changes 8-10-81 LD Fuel Economy Labeling Policy Change 8-14-81 LD Test Fuel Temperature for Precondi- tioning 8-20-81 HD Heavy-Duty Engine Application Format for 1983 Model Year 10-14-81 Waiving of the PCAFE Deadline for 1982 Model Year 10-16-81 Revised Running Change Request Form 10-26-81 Questions on Revised Certification Procedure 12-04-81 Schedule for Second Edition of 1982 Gas Mileage Guide 12-09-81 Vehicle Change/Addition Implementation Concurrent with Change Submission to Administrator--Confirmatory Test Ten-Day Notification Period 12-17-81 Suspension of Telephone Hotline 12-17-81 HD Test Procedure Change for Heavy-Duty Certification Engines