LA 318s can be built to be respectable in the HP/torque figures, but most people just decide to build the 360 instead.
My LA 318 is an 89 with a roller cam and TBI fuel injection and is rated at only 185HP, only 10HP more than the non roller cam with a carb.
These are not high revving engines and headers will be of extremely limited benefit and likely a detriment at lower rpms, where the grunt is more desirable in a camper van
The 2 barrel carb is certainly a limiting factor.
The rear gear ratio is a huge factor. 3.23s were put behind many 727s and it is too tall for when a camper conversion is added. My dodge has 3.55 rear gear. I turn ~2100 rpm at 65mph/~105 KM/h in overdrive and Locked up with an A-500 transmission. In third it is about 3000 rpm at 65mph
Making one of these into a 4x4 is a serious project. If you have the funds for that conversion, then you have the funds for a built 360.
The 727 is a capable transmission. Am not quite sure exactly how much torque it can handle though.
Best of luck with this project.
