Lightnings have GT40 heads stock.If you want to upgrade AFR,Trickflow,Edelbrock and a few other companys make nice aluminum heads that'll make allot more power than the gt40s.GT40 headers are for the GT40p heads which require a special header the Lightning heads do not.If you want to replace the stock headers Bassani sells shorty's that'll bolt up to the stock exhaust.If you plan to do a full exhaust system i'd recomend saving your money and getting one of Pickrel performances longtube setups they're unmatched in power and quality.