Start with bfi then then a cat back exhaust with x pipe and remove a pair of your mufflers two is plenty or get rid of will of them and replace with high flow if sound isn't a issue and don't go too big on exhaust a1/2 bigger or stick size and a smoother path better bends than factory. Last but not least a set of headers and a tune. All together just give around 40-50 go to the wHeels
put a cam, exhaust and headers in and see if anything happens. i swear no ones tried it and posted about it on the internet. while you're at it make a better intake manifold! this little v8 has to have something it can gain. if only i could justify with proof that a good tune and a proper street cam can make significant gains i'd opt to buy them.
damn american v8's and their available power! i envy you!!!