I have a Dodge 3/4 ton custom camper van with a 318 in it. Looking to upgrade the exhaust fir even just a little boost in power and hopefully a little better gas mileage.it’s a heavy, loaded down ****. Was leaning towards putting some shorty headers on it with a cherry bomb turbo exhaust but a friend steered me away from that. He suggested just going dual exhaust but with different exhaust manifolds, not headers and using dyno max mufflers. My question is are there manifolds off of Other Dodge motors I can use on the 318 that could give me a boost or would it be better to just go the shorty route? OR is there something else I am completely missing? This is kinda new to me, so go easy. Thanks!