I can’t recall where I read this, but it is a good ”thing to know” if you’re looking to replace the rear lens of your Federal siren: Apperently, Federal used the tail light lens from the 1954 Oldsmobile! Very easy to source on FleaBay.
@Skulldigger, I was thinking of you when I posted this...I couldn’t remember if was a Federal siren or something else. I recall you thread on making your own replacement. Here’s a site that may help you in your next attempt:
How you can replicate a tail light lens of any car using optically-clear resin.
www.smooth-on.com
Good to know @cmb56. That pretty much tells me it was originally an Olds
lens used by Federal. Guide is almost exclusively GM and they always incorporate the model year in the last two digits in the part number (that’s how you can identify the year of a classic auto, in case you were wondering if you were looking at a 62 or 63 Impala).
The 1956 Chevrolet lens is smaller in diameter than the Oldsmobile tail light.
One thing to consider is buying RED led bulbs to replace the original bulb. From memory, it is a 1156 single contact bulb with 2 retaining pins horizontally opposed. I used " 1156 BA15s 68smd led backup reverse tail turn signal bulb Red " in my siren rear light. The clear LED bulbs will give the lens a washed out look, and the red bulb accentuates the red color.