hey guys my first post on here I've been trying to look for the answer and have found some info but not enough to convince me.

I am looking to buy a 1999-2002 Chevy Express or Chevy Astro (Cargo).
I will be using it for dj business so the equipment eventually will be pretty heavy. I am not sure if the astro will be enough payload but if i can find one for the price i want I will get it.

My question: is there a big MPG difference in the 4.3L vs 5.0L engine? I found a 2001 G2500 V8 ( i think there is only 5.7 no 5.0 in 2001 models?) with 200k miles for $1700 in great condition,Also 5.0L vs 5.7L?

and also what is the life on these beasts (with proper maintenance) is 200K a lot? I will only use this van for couple years then buy near brand new one after that. Not going to do a huge amount of miles but I need decent mpg because then i will lose a lot of money from the DJ Jobs if I need to put it in the gas tank!

The theory Ive been reading is that the 4.3 will have to work a lot harder and will actually get only 1 maybe 2 better MPG when empty and actually same if not less when loaded with heavy cargo (1500lbs or so).