I have the 1406 on my dd also. very easy to tune and stays tuned. starts the same every morning and performs great...so long as i don't leave the pavement.
I'm not familiar with their off road kit, but I am familiar with the Q-jet i"ll be putting on there soon...
on a side note to tuning the 1406, and someting I haven't messed with. It seems tip in throttle response is almost too much. Like its hard to ease away from a stop light. It kinda jumps forward into part throttle. I have to really concentrate to crawl forward. Its kind of a pain in parking lots because its like i'm gunning the engine instead of idleing through the parking lot like i'd like to. anyone else experience this?
The Edelbrock carb is very easy to tune...if you don't have an owners manual, you can download it from the Edelbrock website.
It tells you step by step how to tune with jets, metering rods, and metering rod springs...there are also 3 settings on the accelerator pump that can be adjusted.
You can order a kit that has several jets, metering rods, and step up springs.
I spent an afternoon tuning mine and what a difference it made it both performance and gas mileage.
The offroad needles are spring loaded so you don't have flooding issues when offroading or during hard cornering, acceleration, or braking. They are very easy to install too.
All in all, the Edelbrock carbs are very easy to tune once you learn how...I hear so many people bash the Edelbrocks because they don't work perfectly out of the box. No carb works perfect out of the box...all carbs need to be tuned to the specific motor they are installed on...it just takes a little time.
Also the 1406 comes from the factory for fuel economy and the 1405 is for performance...difference is in the primary jets, metering rods, and step up springs.