This auction is for a NOS brake master cylinder in MINT condition. GM part # 5454503 ( Delco Moraine casting # 5454530 - 1 1/8" bore ). This is a VINTAGE factory original " MADE IN THE USA " quality part General Motors part. I had this master cylinder in dry storage for many years and actually forgot I had it.  Will fit 1955 1956 1957 1958 1959 Chevrolet 1/2, 3/4, 1 Ton Pickup Truck Series ( 3100, 3200, 3600, 3800 ). Also fits 1955-59 GMC Truck Series ( 100, 150, 250). I have been selling on eBay for over 23 years and have a 100% positive feedback rating, so buy with confidence. Combined shipping discounts apply on multiple purchases whenever possible. Questions are always welcome, so don't hesitate to ask. Also be sure to check out my eBay store for more Vintage & Classic parts, accessories and auto literature. I list a large variety of NOS, NORS and quality used parts every week, so check back often.