Yeah, they should. You'll want about 6.5" back spacing. Go with a 245/40/18 up front, and a 275/35/18 out back to get closest to stock diameter. You could maybe squeak out a bit more on both, but you're on your own at that point. Try flipping the quad shocks, which should give you the clearance you need, and if they don't rub anything leave 'em be. You may have to roll or cut the rear fender lips and take a hammer to the inner tub as necessary. It won't take much. If the quad shocks do rub, then you can remove them, but that may, probably will, induce wheel hop under heavy acceleration with a sticky tire. That takes parts and knowledge to get rid of, and we can help you, but it may not be worth it to get adjustable
control arms, set pinion angle, reinforce torque boxes, etc... Or, if it's just a cruiser/show car, then you might not care to launch hard.
I've got 255/40/18s up front, and 285/40/18 on one of mine with stock tubs, but then again a lot of stuff has been done to make that work, and they still rub a bit up front on full compression.