How hard are they to install........and about how long do you think it would take.....?

 

Not 100% on the HEMI since i did mine on my 4.7L //
But to give you an idea if you remove the front two wheels and plastic shround in the wheel wells its all pretty much right in front of you. Took about 2.5hours and a 6-pack but my factory bolts werent to bad so only 1 broke.. if more break this can become many hours.. Steering shaft might get in the way a little but I did it with out moving it

 

Not hard, just a PIA and time consuming. You won't get tons of power out of those. maybe 5rwhp at most. Your exhaust tone will change a little though.

 

Mine really woke my truck up... Yes, takes the wheels n liners off. The worst part with my install was getting the manifolds off. Took about 4 hours i think.