Mid Frame boxing plates CNC cut from 3/16 steel. I use 3/16 steel for its strength. Remember, you will be welding your Transmission Mounts to these plates. Personally I don't trust using 1/8 inch or 10 gauge plate for this application.
These are used along with the front boxing plates I build. They install behind the front set and extend back to just in front of the rear cross-member. Take a look at the pictures to see how far rearward they extend. These look like they are straight with parallel cuts, however they are not.They are 3/16 taller in the rear. That's a 3/16 taper in 48 inches. Installing these plates will strengthen the frame and add lots of rigidity.
These are built to the inside dimension of the frame, this allows you to fillet weld them in place top and bottom. Then grind them smooth and still have plenty of material for a strong attachment.
These plates are precision cut, every set is the same. I spent numerous hours getting the design/shape of these just right. I have test fit them in multiple frames, they fit them all really well! The inner flanges may be slightly bent up or down a bit, easily fixed with a large crescent wrench or a Hammer. Please remember to install cage nuts inside the frame before installing any boxing plates.
If not you will not have anyway to attach your cab and bed. Weld plates slowly and skip around to keep from warping the frame. These will fit 37 38 39 40 Chevy and GMC 1/2 Ton Truck Frames.(Possibly Others Years, but please verify before Purchasing). This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts & Accessories\Other Car & Truck Parts & Accessories". The seller is "sscustomclassic" and is located in this country: US. This item can be shipped to United States, New Zealand, Fiji, Papua New Guinea, Wallis and Futuna, Gambia, Malaysia, Taiwan, Poland, Oman, Suriname, United Arab Emirates, Kenya, Argentina, Guinea-Bissau, Armenia, Uzbekistan, Bhutan, Senegal, Togo, Ireland, Qatar, Burundi, Netherlands, Slovakia, Slovenia, Equatorial Guinea, Thailand, Aruba, Sweden, Iceland, Macedonia, Belgium, Israel, Kuwait, Liechtenstein, Benin, Algeria, Antigua and Barbuda, Italy, Swaziland, Tanzania, Pakistan, Burkina Faso, Panama, Singapore, Kyrgyzstan, Switzerland, Djibouti, Chile, China, Mali, Botswana, Republic of Croatia, Cambodia, Indonesia, Portugal, Malta, Tajikistan, Vietnam, Cayman Islands, Paraguay, Saint Helena, Cyprus, Seychelles, Rwanda, Bangladesh, Australia, Austria, Sri Lanka, Gabon Republic, Zimbabwe, Bulgaria, Czech Republic, Norway, Côte d'Ivoire (Ivory Coast), Kiribati, Turkmenistan, Grenada, Greece, Haiti, Greenland, Yemen, Afghanistan, Montenegro, Mongolia, Nepal, Bahamas, Bahrain, United Kingdom, Bosnia and Herzegovina, Hungary, Angola, Western Samoa, France, Mozambique, Namibia, Peru, Denmark, Guatemala, Solomon Islands, Vatican City State, Sierra Leone, Nauru, Anguilla, El Salvador, Dominican Republic, Cameroon, Guyana, Azerbaijan Republic, Macau, Georgia, Tonga, San Marino, Eritrea, Saint Kitts-Nevis, Morocco, Saint Vincent and the Grenadines, Mauritania, Belize, Philippines, Democratic Republic of the Congo, Republic of the Congo, Western Sahara, Colombia, Spain, Estonia, Bermuda, Montserrat, Zambia, South Korea, Vanuatu, Ecuador, Albania, Ethiopia, Monaco, Niger, Laos, Ghana, Cape Verde Islands, Moldova, Madagascar, Saint Pierre and Miquelon, Lebanon, Liberia, Bolivia, Maldives, Gibraltar, Hong Kong, Central African Republic, Lesotho, Nigeria, Mauritius, Saint Lucia, Jordan, Guinea, British Virgin Islands, Canada, Turks and Caicos Islands, Chad, Andorra, Romania, Costa Rica, India, Mexico, Serbia, Kazakhstan, Saudi Arabia, Japan, Lithuania, Trinidad and Tobago, Malawi, Nicaragua, Finland, Tunisia, Luxembourg, Uganda, Brazil, Turkey, Tuvalu, Germany, Egypt, Latvia, Jamaica, Niue, South Africa, Brunei Darussalam, Honduras.