Stock 318 bolt on performance modifications

Second dual exhaust, don't waste the money on the "340 manifolds", they're worth 3-4 horsepower tops, see here http://www.moparmusclemagazine.com/techarticles/engine/mopp_0307_mopar_crate_engine_exhaust/photo_17.html, expensive to ship, preposterously dear for what they are and there's better places to put money. If you are OK with cheap headers get cheap headers and a summojegsalocalmufflershopomatic dual exhaust, or have a muffler shop build some downtubes from your stock manifolds (delete the EGR flapper wheel nonsense with some jbweld and bolts or all thread and washers or whatever level of ghettoness you are comfortable with) piped to a dual system.

As a dude who is putting a 4bbl into a car that originally had a 2bbl, I can tell you this. It's not as "put them there 600 four burrel on and whoop she go" as it sounds in a forum thread or article. You're gonna be pulling the distributor and the intake manifold, which is a beast to do yourself without a crane or a young, vital backbone, strong and wide. As well as disconnecting all the sensors and hoses that go along with that process. Then, once you get the sucker back into place, you will realize that all of your linkages are now worthless. Your throttle cable doesn't reach right, the kickdown linkage isn't in the right place. So you need to get a stocker 4bbl setup or a Lokar kit (which is pretty cheap and pretty nice, TBH, I had a lot of haterade before it showed up in the mail, it feels nice and strong), and switch out to that.

If I had it to do again, maximizing dollar to horsepower, I'd probably do dual exhaust, a shift kit, a new cam, DIY HEI on a recurved distributor, and either rebuild the BBD or replace it with a motorcraft 21xx, on a "big holley" adapter plate, which is what the BBD-affected performance jeep folks appear to favor. That would be a big kick in the shorts <$1k even if you aren't shopping for sales and being frugal.