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Mark III passenger side footbox too small

317 views 10 replies 7 participants last post by  ABC123 
#1 ·
Hi,

I’d like to extend my Mark III passenger side foot box out into the engine compartment as shown by the solid yellow line in the picture, the dashed yellow line is where the existing panel will be bent out. The panel will run parallel to the round frame tube (similar to the driver’s side) Will this cause any clearance problems? I searched the previous messages, but did not find anything specific. I’ll be running a 302 with the 4 into 4 FFR headers.

Thanks!

Tony F

 
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#3 ·
Thanks Paddles, I’ve noticed that that Linwood's box does not extend the foot box over towards the engine, or it does not state that on his website. It only claims to extend the box downward and forward. The box really needs to be wider too; but I think it might interfere with the headers if it were widened towards the engine. I was hoping someone could confirm this?

Tony
 
#4 ·
Tony,
I just did this very modification exactly as you described. Very easy, but time consuming to get the metal bends all OK. I used a flat sheet on the front facing panel (call this panel #1) and ran it over to the 4" tube then I used another flat panel (call this panel #2) that ran along the 4" tube and intersected with your dashed line. I trimmed the existing metal at the dashed line and rivited it to panel #2. I ran these up to within about 2" of the top of the foot box and made a cap with tabs that riveted to panels #1 and #2 and the existing box. The reason that I did not run it to the very top was so that I didn't want to mess with the complex corner joint plus I thought it best to leave that corner alone as it was well formed and provided a lot of strength to the box.

The bottom edge of Panel #2 will be riveted to the 4" tube for strength.

As far as clearance problems, I don't see any yet except that I'm about 1/2" from the headers (stock headers).

Doing this mod just about doubles the width of the useable footbox floor. I'm very happy with it.
 
#5 ·
Originally posted by Tony_F:
Thanks Paddles, I’ve noticed that that Linwood's box does not extend the foot box over towards the engine, or it does not state that on his website. It only claims to extend the box downward and forward. The box really needs to be wider too; but I think it might interfere with the headers if it were widened towards the engine. I was hoping someone could confirm this?

Tony
You are correct, Linwood's kit does not widen to the left. My MK II kit does.. but ive not decided or had a chance to look at the mkIII to see if there is an opportunity here. My MKII kit does not fit the MKIII. So, I guess im saying that SO FAR, no one has met this need. Its gonna be hard to design one that widens to the left and still allows big engines and big headers.

CobraEarl
 
#6 ·
Doing my own right now on a MKII with 4 into 4's on a 302.

When it's done, I'll put up pics!
 
#7 ·
Chepsk8, Any info you or anyone else can provide will be appreciated, I’m not looking to design a universal foot box kit, but merely solve my particular issue.

I’d drop the engine in and check, in fact I plan to, but my headers are backordered. Surely, someone has done this already on a 302 Mark III with 4 into 4s? If not perhaps, someone can measure and take a few pictures of the stock 4 into4 setup; the main thing is how far, if any, the headers protrude past the large frame tube and how high are they from the tube.

Tony
 
#8 ·
Thanks DMW, it sounds like we are on the right track. My thoughts were to do something very similar.
 
#9 ·
I did something similar with my Mk1.5, but I'm using J-pipes. I started with CobraEarl's kit, then decided to extend it another 3" forward. Below is one picture that's very similar to what you're suggesting. I've looked looked at mine and then compared to cars using 4into4's and it looks like its too close to tell if it'll clear. I'd really suggest installing engine and waiting for the headers before starting fab.
 
#10 ·
Thanks Jeff, it sure sounds like it has not yet been done, doesn’t' it? Waiting may be the best option at this point, since Chepsk8’s and possibly other’s are in the works.
 
#11 ·
Originally posted by Paddles:
I used Linwood's (FFMetal.com) passenger footbox kit on my MkIII. It fits perfectly, and I have no clearance issues with my 460 and the 4-into-4 headers.
I did not know my foot box kit had been used on a MarkIII. Thanks for the heads up and your kind words.

My foot box is no wider then a MarkII but it is wider then a MarkIII. My kit will not work with a 4.6 but should work with any other motor header combination. Be careful, if you move your foot box closer to the motor then mine you will limit the the number of available headers you can use.
 
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