I would think you could adapt a charcoal canastor from almost any car to serve the function of odorless venting. You would need to have a plan as to the location you would put it and then at a yard that lets you walk and look you could find what would fit the best.I'm not at all familar with the car but all later cars had the charcoal canistors to prevent this problem. <P>Your gas leak could be another problem.If you commonly park facing downhill it may be a good idea not to overfill. A charcoal canister is for fumes not raw gas.<P>This kind of problem requires resourcefullness and creativity but is not the kind of problem to bring a good car down.
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86 LeSabre Limited Coupe 3.0 litre
86 Riviera 3.8 litre
91 Regal Limited 3800 cc traded for '99 "88" anniversary edition - mistake
82 NewYorker 318 ci
75 Royale convertable 350 ci
76 Royale 2dr Hardtop 350 ci
97 LSS L67 3800cc SuperCharged