63-66 Back-up Lens question

[David L.]

Each NOS back-up lens (purchased in 1980) on my 1966 Corvette has "GUIDE" and "B1-58" molded in to the plastic. I know this lens (GM # 5948757 in Gr. 2.697) was also used on 1958 Chevrolets (exc. STA. WAG., SDL). The description for part # 5948757 in my 1963 Chevrolet Parts Catalog is as follows:
"LENS (Clear plastic - molded 5948757)" which I think was a care over from the 1958 Chevrolet catalog.

Do original 1963-1966 Corvette back-up lenses have "5948757" or "GUIDE" & "B1-58" molded on them?

[Wayne M.]

Re: 63-66 Back-up Lens question

Dave --- '65 TIM&JG says "GUIDE B1-58" at center cone. My two cars have B1 (or could be BI), dash, 58. My backup lenses are not original, but at least 20-30 years old, therefore GM.

Red tail lights per '65 TIM&JG: RI 58 (ie. no dash), 58. Then at bottom edge in script is "Guidex".

[John H.]

Re: 63-66 Back-up Lens question

The "58" refers to the model year when that lens design was first certified to meet SAE photometric requirements (long before DOT lighting certification), and generally also indicates the year of first usage.

[Wayne M.]

Re: 63-66 Back-up Lens question

The "58" refers to the model year when that lens design was first certified to meet SAE photometric requirements (long before DOT lighting certification), and generally also indicates the year of first usage.

John -- ever return to your parked '65 to find some know-it-all explaining to his friend that this "Corvette is a 1958", after a quick check of the tail lights ?

Corvette might have been an exception in that the same tail light design was used over many model years, but if it changed annually, as with most passenger cars, would the year digits change as well, and would the "know-it-all" be correct, by default ?

[John H.]

Re: 63-66 Back-up Lens question

John -- ever return to your parked '65 to find some know-it-all explaining to his friend that this "Corvette is a 1958", after a quick check of the tail lights ?

Corvette might have been an exception in that the same tail light design was used over many model years, but if it changed annually, as with most passenger cars, would the year digits change as well, and would the "know-it-all" be correct, by default ?

Wayne -

Yes, I've seen the "taillight ID experts" at work.

In the days before MVSS and DOT regulations, every "new" lens design was certified to the SAE requirements, with the date molded into the lens.

[Ronald L.]

Re: 63-66 Back-up Lens question

And they are there to this day on the the lens, now DOT, but same thing, you will have a part number, code, and then the cavity number of the lens. Usually down towards the bottom in an area you can't see if you weren't looking for them, but they are there.