A 78 LRE and an 85 swb D150 should be the same frame. What trans does the 85 have in it now? The rear axle in your truck could make a difference as well.
If the 85 currently has a 727, or a 4 speed OD, the current drive shaft should work. If the LRE driveshaft is available, it would also work, provided your truck is a standard cab with a 9 1/4 rear axle. All you need is a driveshaft from a short box truck, with the same cab and the same rear axle as yours that has a 727, built between 73 and 93.
As far as the motor work, the same things done with an LA 360 will net more power then the 318 will. Gene
Maybe I wasn't clear. Truck had 318 with a 904 and 9-1/4 rear. Swapping in another 318 I have ready to go with a 727.
Anyone know the driveshaft length with this combo?
Trying to get an idea what else might have the correct size besides SWB Pickups which are fairly rare in junkyards in Texas.
Ramcharger is same wheelbase? Vans?