i love my fj 60 but man it it gets bad mpg, can you swap a old chevy 2 bbl on these?i am guessing iam getting 8-10 mpg off road where my 4 runner gets 25 -30 mpg off road.i have gotten 400 mi. on a tank in my 97 4-runner and about the same in my tacoma but the 60 gets about 175 mi. out of a tank just putting off road.freeway is way differant .