HELP WITH FITMENT ON TRUNK FLOOR EXTENSION

[68RT440]

Hey guys, Im starting to fit up the sheet metal on the back of the '68, and Im running into a few issues. Im fitting up the quarter panels (CBD), and Im having some issues with the trunk floor extensions (AMD). Now let me start with saying that I had to cut the outer wheelhouses(AMD) because the quarter lip and wheelhouse lip was about 1/2-3/4" apart. Im sorta having the same issues with the trunk extensions, but where the wheelhouses were cut and dry as for where they needed to go, the trunk extensions are proving to be a little harder. Basically, Im having a hard time getting the correct angle of the extension where it drops off to correctly meet the quarter at the bottom. If I let the quarter relax where it needs to be, the bottom of the extension is about 1/2" higher, and If I force the quarter up to meet the lip of the extension, then it distorts the quarter badly. If I clamp the quarter where its relaxed, then the quarter sits further past the lip of the extension. Here are some pics to better explain:

Here is how it sits if I let the quarter sit where it is correct and clamped:



Heres how it sits in the wheel well. You can see how much I had to cut and fill on the front part of the extension to get it to meet the quarter. I had to do this about 3/4 of the way around the outer wheel house:



This is the gap that I have when the quarter is relaxed. If I try and clamp it where the flanges are over top of eachother, the quarter pushes way out at the bottom and doesnt line up with the wheelhouse/extension in the wheel well. To me it looks like I need to cut the lip off of the extension and add a filler piece, but I wnt more input.







Heres how the quarter sits when relaxed. This is another issue that Im having. I dont know what the correct sweep of the lower quarter should be, so I dont know what to adjust. Im sure that the skin is stamped close, but by tugging and pulling on the extension, I can change the angle of how it drops off the meet the quarter, but nothing else looks right. Also, inside the trunk, should the gap between the extension drop off and the inside of the quarter be the same width from the wheel well to the tail panel? Thanks for the help guys and sorry about the million questions.

[hemi-hampton]

I would say instead of moving 1/4 to meet extension, move extension to meet 1/4. BUT, I assume you can't do this because you already fully welded extension. If so that may of been your mistake. LEON.

[68RT440]

yea the extension is already welded in place. The problem is that the other places like the trunk floor, the wheel housing, and the rear crossmember where the extension welds to is right on the money. So I figured that Id make the other 3 locations fit and have one thats off rather then the opposite. I have no trouble cutting the bottom of the extension to fit the quarter, but I just wanted to make sure there werent any other tricks that Im missing...

[Dino]

Never compromise the fit of the visible panels, ie don't mess with the quarter or force it where it doesn't want to go.  Make sure both sides line up.  Things on the inside are out of sight, trunk extensions can be modified without anyone knowing.  Since it's welded it'll be a bit trickier so be prepared to cut and weld a bit.  First of all the edges of quarters and extensions are not cut to the finished dimension, you do that after welding is done.  You will have to bend the extensions so the edges line up a little better and you may end up flattening the existing edge of the extension and bending in a new one.

This stuff rarely fits so you need to do whatever you can to make it fit a bit better but again, do not try to alter the quarters or you may ruin them.

[68RT440]

Ok thanks Dino, the CBD quarters are beautiful and I would do whatever possible not to take a cut off wheel to them. I had to cut and splice the outer wheelhousing so it sat flush with the lip on the quarter on both sides, but I guess working with ill fitting sheetmetal is better then working with rusted sheetmetal..lol. Like I said I have no issues cutting up the extension, but before I did that i wanted to make sure that you experienced guys didnt know something that I wasnt aware of...

[Dino]

i wanted to make sure that you experienced guys didnt know something that I wasnt aware of...

Just one and you figured it out, the new stuff doesn't always fit. 

Frustrating as it is to try and get it all to fit, it is indeed better than not having the metal at all.  From the looks of it I think it may be a good idea to look into cutting slits front and back so you can bend the existing curves a bit more instead of creating another.  With the extension fully welded it doesn't leave you a ton of options so look it over carefully, figure out where the metal needs to go and get your cutting wheel out.

[68RT440]

Im thinking of doing what I did on the wheel house. I clamped the quarter in place and then cut the flange off of the wheelhouse, then clamped the flange to the quarter, then I filled the gap accordingly. What Im thinking of doing is cutting the bottom flange off of the extension and clamping it to the quarter, then filling in the gap. It worked out really well on the wheel housings and they ended up being right on the spot with measurements taken from another car, so it seems that these pieces are out of spec, then once modified they actually become more correct to the factory piece...

[Dino]

Im thinking of doing what I did on the wheel house. I clamped the quarter in place and then cut the flange off of the wheelhouse, then clamped the flange to the quarter, then I filled the gap accordingly. What Im thinking of doing is cutting the bottom flange off of the extension and clamping it to the quarter, then filling in the gap. It worked out really well on the wheel housings and they ended up being right on the spot with measurements taken from another car, so it seems that these pieces are out of spec, then once modified they actually become more correct to the factory piece...

If using a filler piece brings it closer to stock spec then that's a bonus.  Go for it!

[hemi-hampton]

Im thinking of doing what I did on the wheel house. I clamped the quarter in place and then cut the flange off of the wheelhouse, then clamped the flange to the quarter, then I filled the gap accordingly. What Im thinking of doing is cutting the bottom flange off of the extension and clamping it to the quarter, then filling in the gap. It worked out really well on the wheel housings and they ended up being right on the spot with measurements taken from another car, so it seems that these pieces are out of spec, then once modified they actually become more correct to the factory piece...

If using a filler piece brings it closer to stock spec then that's a bonus.  Go for it!

I 2nd that motion. LEON.

[68RT440]

thanks for the help and support fellas!