^^^what they said. sawzall is no doubt cheaper, there will be a huge differnece between just fender trimming and doing it right. Add small bodylift too fender trimming, you might be able to get by with just 2" spring lift, then you won't have to re-engineer the steering, pinion angles, etc.
Don't forget to upgrade the AMC20 to one piece shafts, weld the tubes to the center sections, maybe truss it. I have a bent housing to show what happens if you beat the snot out of and AMC20 with 35s. Mine was widetrack, yours should be narrow, maybe you'll be fine.
You can do it without regearing, but after accelerating 0-60 in 4 days, you'll rethink keeping your stock 3.55 gears.