1975 Convertible Glass Codes

[Alger R.]

The white script code on my 75 Convertible Lt & Rt Door Glass includes the code "M74". Per the NCRS "Technical Information and Judging Guide" (page 44), the specification for convertible glass should be "M75" with the coupe having "M74". Does the judging guide possibly have these codes reversed? Any help out there would be appreciated. Thanks, AL

[Dick W.]

Re: !975 Convertible Glass Codes

Alger, do the date codes line up?? If so it is possible that there is an error in the manual You should contact Marvin Burnette, the team leader for 1973-'77

[Alger R.]

Re: !975 Convertible Glass Codes

Alger, do the date codes line up?? If so it is possible that there is an error in the manual You should contact Marvin Burnette, the team leader for 1973-'77

I am sure the glass and codes are correct for the car. I saw a previous forum question (2006) asking similar question and the answers ranged from Coupe = M74 to M74 = 5mm thickness??. I suspect there may be an error in the manual and I will most likely contact Marvin. Thanks, AL

[Harmon C.]

Re: !975 Convertible Glass Codes

I am sure the glass and codes are correct for the car. I saw a previous forum question (2006) asking similar question and the answers ranged from Coupe = M74 to M74 = 5mm thickness??. I suspect there may be an error in the manual and I will most likely contact Marvin. Thanks, AL

The convertible glass is not the same shape as coupe glass and the dates are correct so you may have found an error.
Lyle

[Dino L.]

Re: 1975 Convertible Glass Codes

The M74 represents an M number or a construction approval type submitted by LOF to NHTSA as proof to meeting FMVSS (federal motor safety standards)...I remember calling LOF on this some time back ago and I thought the difference is glass thickness, look through the archives.
probably 4 mm versus 5 mm. They both were tempered and both were made from green tinted glass, the silk screen or other atrributes dont impact the M number. M number is more about safety...

[Alger R.]

Re: 1975 Convertible Glass Codes

The M74 represents an M number or a construction approval type submitted by LOF to NHTSA as proof to meeting FMVSS (federal motor safety standards)...I remember calling LOF on this some time back ago and I thought the difference is glass thickness, look through the archives.
probably 4 mm versus 5 mm. They both were tempered and both were made from green tinted glass, the silk screen or other atrributes dont impact the M number. M number is more about safety...

There was some information on the forum in 2006 regarding the code being "thickness" but it was one possibility out of several answers. Nothing definitive. My concern has been that my 75 convertible with the M74 code does not comply with the judging manual.