How much clearane is needed to install a 3in downpipe? what tools?

 

The best tools I found were a sawzall and a 2 or 3' long piece of pipe!

Make a few cuts in the cab seam, then use the pipe to bend the seam back. Presto.

 

Not much!
Sawzall to remove it and a porta power to make room for the new down pipe.
It's a pain to get the stock down pipe out.

 

I used a 4 1/2in angle grinder, 3in air grinder and sawzall to get my old DP out. Just depends on which part of the pipe you're cutting as to which tool works best. Clearancing for the new DP is pretty easy, compared to getting the old one out.