I bought this last fall outta GA (I live in southwestern MT). The elevation up here can vary greatly but right around here it's about 4200 to 4500. The van had a lil over 63,000 miles when I bought it. I talked to the original owner who had traded it in to a dealer whom then sold it to a private dealer. I've done a fair bit of maintenance on it and replaced quite a few things (most recently the transmission ). It has almost 100,000 miles on it and it runs good but I would like more power and gas mileage from the 318 if possible. I have been almost exclusively running Valvoline MaxLife (synthetic blend) oil in it since about 65,000 miles with a couple changes of full synthetic max life. It started leaking oil out through back of the intake more so I went back to regular max life and it seems to have slowed or stopped. Anyway, I was looking at the Hughes/Edelbrock Air-Gap intake manifold to replace the factory keg intake and maybe a throttle body from a 360, a true double roller timing set, and some later manifolds and maybe custom dual or a single exhaust. I've also thought about maybe a cam. Now some of this would be subject to running some tests (like compression, running compression, vacuum gauge tests), a possible teardown with inspection and such but are any of these ideas worthwhile and actually helpful or would I just be better off to keep the keg intake, buy the Hughes fix deal for the problem prone plenum gasket, a true double roller timing set, and be done or some other variation? I don't wanna spend $600 on an intake and not feel and/or notice much difference in mileage and power. I know the timing set wouldn't be a bad idea but the rest of my ideas I'm not sure.

 

Hughes makes a intake and throttle body for the 318. Don't know anyone that has used it thought.