I suppose that it is not unusual to need shims between the frame and body, especially on open car bodies like my '21 Touring. The body had been off the frame before I bought the car. There is nothing between the body and frame currently and the bolts and nuts are not tight. The body is in fantastic shape with no rust or repairs from rust in the past. All the original wood is still in place and is rock solid, except for the two tacking strips around the upper back of both seats. The tack strips are new. After finding that a low hood was not low enough to fit I examined some other low hood cars and found that my car will need some spacers/shims under the two front mounting points. The two holes on each side of the frame for the firewall brackets show that the body needs to be raised about half an inch. It also needs some under the right rear mounting point for the passengers side rear door to latch as it should. I had a buddy lift up on the body at the rear and the door latched perfectly. I plan to make a trip to the hardware store in the morning for some fender washers. Any suggestions, tips, or warnings? thanks.
Harbor Freight has packages of several slotted body shims containing different thicknesses, and they're not very costly. I suppose one could use washers, or have convenience. I picked up a pack just to have them on hand. Hope this helps.
Take Care; Behave; "Don't Shoot!" (and)
It's likely the need to shim the front body mounts comes from a bent frame - they tend to sag at the rear engine mounts. If the body bolts are loose, maybe it's more practical to lift off the body and check properly how straight the frame is and correct it - hood fit may be a nightmare without a properly straightened frame..
If bent, it can be straightened as a chassis, one beam at the time, chained to a stronger beam on the floor and with a hydraulic jack pushing it to shape.