I have 1965 Chevy 1/2 Ton with rear factory leafs - everything looks to be factory, nothing seems to be modified - Also the heater Core is under neith the dash inside the cab. All it has is plates bolted on the fire wall which also looks factory. I have never seen this before - I am wondering if anyone has ever heard of this and if this is rare. Appreciate any info. Can also email me at ckwilly@telusplanet.net