Well, IMO, since you have the NP435 and 205 already, you're not looking to a 1/4 mile in 11 secs. Since you're building a trail rig, they truck is light, put a torquey 302 and get an Atlas multiple low t/case. You were willing to spend money on the engine, save it for the t/case.
Ratio's of the Atlas 4Speed are:
1.5:1, 2.72:1, & 4.08:1 Recommended for all applications
2.0:1, 2.72:1 & 5.44:1 Recommended for all applications
2.72, 3.0:1 & 8.16:1 Recommended for all applications
2.72:1, 3.8:1 & 10.34:1 with this low gear ratio, high horsepower engines are not recommended
2.72:1, 4.3:1 & 11.70:1 with this low gear ratio, high horsepower engines are not recommended
Think about it:
NP435 low gear: 8.26:1
Atlas low gear: 11.70:1
rear axle: 4.88:1
That equals 471.61:1 crawl gear. You could climb a 3 story home with no issues while strapped into a lounge chair in the bed.