ok, my s10 3 door has the ram designed box now only problem is the box comes to 3" below the back window. and takes up the whole extra cab. 4.75 cubes. my idea for mounting the 2500d are now limited. can it be mounted upside down? i was thinking of building/welding brackets across roof and mounting upside down. any ideas are helpful

I'm not sure, but heat dissipation may become an issue.

Also vibration, I know my roof gets so hot you can touch it in 80 degree weather

i wasnt goin to direct mount, rather a "bridge" welded between both b&c posts that spans across roof. then build rack for amp that has enough room to put 2 small fans for air movement. that way i can run wires inside the posts and they will be hidden. but question was can it be mounted upside down? i would think so being as its a solid state device, but just not sure

to answer your question, yes, you can mount an amplifier upside down, it won't get a head rush

But would I mount it to the roof? No. Sounds like you have a plan, but still wouldn't be my choice. Do you have a false floor? If so, is there any space below that? How about at a 45 degree angle from top of enclosure to the back side window? Is there any space at the bottom of the enclosure against the rear seat? Any room under the rear seats? Pictures with box in from different angles would be amazing right about now

i would go with a false floor with some fans.

Heat rises, so heat sink should be on top, but if it's upside down then it might not properly dissipate the heat.

This is just a thought, so I could be wrong.

I will take some pics tonite. As far as the floor, that's out. Box sits on floor. Built to go from back of seat to back of cab. My seat literally rests against box. Trapezoid style. There is 6" of room from end of box to side of cab. There is no room in front. The 45 I kind of like and that was recommended by someone else also. What should the rack be made out of? Can i use some of the extra mdf i have, then wrap it? Under the seats is not an option also. I have cut and rewelded the frames to get the seats lower. 2" of room max and floor is not straight. It has ridges built in for structural support.

here are some pics