Drilling through the trunk above gas tank...

[jforest1]

So I have to put some bolts down through the bed of the trunk above the gas tank on my '73 Cuda in order to mount some L-brackets to keep the corpses from shifting around while driving.

Looking under the car, it appears that there is very minimal clearance between the trunk and the top of the gas tank.  Yet I need to put these bolts through.  It looks like there are some ribs in the gas tank.  Are these also on the top of the gas tank (I'm thinking I could possibly position the bolts to sit between the ribs)? 

If so, I've read in the maintenance manual how to drop the gas tank down and have a vague understanding of it.  If there was a way just to drop it down slightly in place so that I might reduce the risk of drilling through it that would be nice.  If not and I have to take it completely off, I suppose it would be an opportunity to paint it.

Any suggestions on the bolts in the trunk or ideas on mounting the L-brackets without drilling through the bottom of the trunk?

JF

[the_engineers]

Shock crossmember is a safer area.  Otherwise, you should be able to loosen the nuts for the straps (near the shackles) and drop the tank down some.  I'd empty it as much as possible to make lifting it back up easier...

[dutch]

the tank is made out of 2 halfs. These are the same stamps, so on the bottom you can see exactly what is on top. A piece of sound deadener is all space between tank and floor. I guess you could drill a hole, but I don`t see how you would get a bolt or nut there without dropping the tank. You will have to drop the valance first. Not sure what these L -brackets are gonna need to hold in place, but there are some awesome glue products available...

[jforest1]

Amplifiers vertically mounted so not too much weight (10 lbs). 

What glue are products are you talking about specifically?  My two concerns are really general vibrations/forces of driving the car making them come lose and in the event of a collision the amps becoming a flying metal projectile into the back seat.

Currently I've got the trunk base (painted), then a layer of Stinger Roadkill (aluminum side up), then carpet. 

I'm guessing if I glue, I'd cut a hole in the roadkill down, strip the metal of paint, and glue to that for best bond.

So there's glue, bolt, and weld.  Any other general options for affixing two pieces of metal to one another?

JF

[74BlueFish]

You could use Pop rivets.   Or other types of Blind fastners similar to Pop, but much stronger.  They will protrude only about 1/4 inch thru the floor.

[jforest1]

You could use Pop rivets.   Or other types of Blind fastners similar to Pop, but much stronger.  They will protrude only about 1/4 inch thru the floor.

Great suggestion.  I think this is the best option for me right now.  Anybody know how thick the trunk floor pan is?  I'm guessing 1/8"?

JF

[burdar]

I tried to quickly do a search for the thickness of an AMD trunk floor but didn't find anything.  The thickness is not going to be anywhere near 1/8".  Most likely half that.

[dutch]

pop out a drainplug and you`ll know.  it`s about 0.1 to 5.0 mm.... depends on the amount of rust... 

[Challenger6pak]

I've always mounted my amps behind the seat, below the rear package shelf, in between the upper shock mounts. 

[jforest1]

I've always mounted my amps behind the seat, below the rear package shelf, in between the upper shock mounts.

Yeah...mine are sort of on display...  I know, I know.   

JF

[MEK-Dangerfield]

Yeah...mine are sort of on display...  I know, I know.   

JF

Truth is, these modern day amps are too pretty to hide. I have mine where Challenger6pak suggested though.

[72cudamaan]

How about mounting the amps on a board shaped to fit the floorpan?
Shape it close enough to the right shape and it can't shift.   

[Challenger6pak]

When I last had a Challenger on the road I had the trunk done very similar to this one.  My amps were mounted in the back by the seat and bass speakers were under the sides. I was able to use L brackets to hold everything down.  You can mount them through the trunk floor where they will clear the outer edge of the tank.  You just have to be very careful.  In the middle I put carpet down to cover my L brackets. 

[mopar12372]

you have a little over 1/4 past the trunk floor . if you have the insulation the distance is more .
 happy drilling!!!!!

[tommyg29]

I agree you can probably drill through with a depth gauge set on your bit that wont allow it to go beyond a mm or so past the sheetmetal, which is probably about 1-2mm thick. Goes without saying...drill lightly and very carefully. But first confirm you do have the insulation sheet on top of the tank. There is also a pair of trunk braces that the tank presses up against which should give you the space you need, but....who knows how your tank is installed? Many cars contain surprises if you know what I mean.
Heres a picture of mine when I cleaned up in that area and replaced my tank last year.