tbi is less fuel efficent than carb in alot of dodge trucks. if you look in the 2nd gen section some of there 318's barely get 15mpg. some of the older carbed 318's with a few certain parts can get between 18-25mpg. there are some engines that are more fuel efficient as fuel inject but not too many.

 

15 in this thing would be a blessing.

 

IMHO, the tbi wont make enough difference to make all the extra work worth it. swap intakes and use the carb. most 70s 1/2 tons had dana 44s under the front, and beleive it or not gm 10 bolt rears.(you know the ones with the c clips in the axels. I know ,I had a 75 4wd and replaced 2 10 bolts before I got smart and put an 8 3/4 in.

 

I may not need to change the engine after all. Dad stopped by and says the noise is in the lifters. If we can find where the oil is comming from in the front and fix it then this one may run a bit longer for me.

 

Found the oil leak. the front balancer had slipped and was rubbing the front cover, run a hole right in it. going to pick up a new cover and balancer and fix it.

 

The only way it'd be worth the swap would be a Magnum motor, but I still think you'd average 12-14mpg.