I need a little extra Axel width on the rear of a '30 Model A and want to add some 1" wheel spacers. These spacers are aluminum and are attached to the Axel with the stock studs, the wheel is attached with the spacer studs. The car weighs about 2500 lbs and has about 220 HP.

Are these type spacers safe, some say spacers are not to be used.

My 2007 Chevy Colorado has similar spacers on the front end, they are factory parts, not sure why Chevy engineers designed the front hubs this way.