If you are dealing with a vehicle that has an open channel, then you should box in the frame rail prior to mounting the new bracket. The slots of the mounts are designed to give you side to side adjustments. The slide lock tab will lock the mount down once the engine location is selected. The slide lock tab does require welding to the mount but can be bolted for securing and assembly purposes so you can relocate your rig to your local welder.
These mounts will fit frame widths up to 27-3/4. The engine mount kit includes two engine side mounts (3/16" thick steel), two weld-in gusseted frame mounts (1/4" thick steel), and rubber mount kit. Note: 713001-S is used with All GM V8's & 4.3 V6 with a triangular / 3-bolt boss on the engine block. If using a new Gen III / IV, LS-Series V8. WARNING : This product can expose you to chemicals including Styrene, which is known to the State of California to cause cancer.This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts & Accessories\Engines & Engine Parts\Engine Mounts". The seller is "wundercarparts" and is located in this country: US. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech Republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South Africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi Arabia, United Arab Emirates, Qatar, Kuwait, Bahrain, Republic of Croatia, Malaysia, Brazil, Chile, Colombia, Costa Rica, Dominican Republic, Panama, Trinidad and Tobago, Guatemala, El Salvador, Honduras, Jamaica, Antigua and Barbuda, Aruba, Belize, Dominica, Grenada, Saint Kitts-Nevis, Saint Lucia, Montserrat, Turks and Caicos Islands, Barbados, Bangladesh, Bermuda, Brunei Darussalam, Bolivia, Ecuador, Egypt, French Guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman Islands, Liechtenstein, Sri Lanka, Luxembourg, Monaco, Macau, Martinique, Maldives, Nicaragua, Oman, Peru, Pakistan, Paraguay, Reunion, Vietnam.