Not an expert on the belts... though I'm thinking of the backseat anchored 3 point. On the seats... I think the stock E body seats basically suck for both handling and distance driving. No side support and weak back support. For OE resto, no question fix up the stockers. For handling you really need a better seat. My solution was Scat rally seats. Good side support and good back support. Available at reasonable cost from Summit with matching brackets for an "E". Just have to hacksaw off 2 of the 3 mounting locations to get the seat at the right height. Not a full race seat but 1000% better than stock. Also does not look out of place too much in a 70's car. Comfortable as well for long drives for me at least (eg. IL to CA in 3 days, back in the same time).