I do not recommend it. Back on my 76 a few years ago, I used a ratchet strap to pull the leaf springs towards each other. I used the isoclamp F body mounting plate. I just drilled the hole so the rear was set back. I notice recently on my current F coupe that there a rub marks on the inner quarters (non tubbed) The factory wheels had been riding some wide meaty tires and when the car would squat, there was rubbing. By adding the plate you mention you will get real close to the critical area of the inner 1/4. Plus by drilling the hole to set the rear back, you may be able to keep the stock drive shaft. I'm currently waiting to trash my 8 1/4 sure grip, to stuff my 8 3/4 741 case rear.