reinforcing convertible chassis

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jimchil

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1973 blue Convertible 351 Windsor modified. Automatic.
[url=https://ibb.co/ZWtyVsL][img]https://i.ibb.co/Pw3BNpm/20190517-080704.jpg[/img][/url]

[url=https://ibb.co/6sdD8Vj][img]https://i.ibb.co/MNXPfWF/20190517-080704.jpg[/img][/url]
Hello. I am new here. Happy to have found this group. I was told the 73 convertible chassis could use some extra support to prevent flexing. I ordered some global west sub frame connectors. Would you folks want to suggest anything more? A Monte Carlo bar would have to be curved for my MSD distributor. I like the idea of Global West X support on earlier Mustangs. Looks strong. I was even wondering if a simple roll bar would be a good idea. Thank you.

 
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1973 Ford Mustang Q-code convertible
Welcome from the Netherlands!  

This might be an option for you :

 http://www.tinmanfabrication.com/index.cfm/page/ptype=product/product_id=58/category_id=123/mode=prod/prd58.htm

I have no experience with these, but might be a solution for you. I did look into this option as I have a convertible myself , which is in pieces at the moment for a full restoration. I have decided to keep the car as original/stock as possible instead of going into the restomod direction,so I don’t mind the 1970’s driving quality myself. 

I am not sure if a roll bar is possible on the convertible... I definitely haven’t seen one before!

Please post some photo’s of your car! People on the forum love photo’s  :D

 
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1973 Mustang Grande 351C 2v
Welcome from Iowa and post up some pics. The addition of the subframe connectors will help tremendously with body flex especially in the vert. Unless you are going to road race it I think you would be good to go with that addition.

 

JohnnyJ

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1973 Convertible. 1989 306 roller block with ported heads b303 cam, Hughes street rod converter. The car has 91k original miles. Has been painted once but is unrestored. I put the new engine in at 89k. It has about 280hp which is about double the original.
I added the global west connectors and that eliminated about 80 percent of the cowl shake,

And that's enough for my use. Monte Carlo bars are inexpensive but I don't know if they stiffen the chassis.

 

7173Vert

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1971 Convertible, 1973 Hardtop
My thoughts are that these vert’s were already built to handle the power and torque from the factory. As most know, I restored my factory J Code vert as close to original as I could. The engine, although the original block, heads, etc. was internally massaged to provide more subtle hp and torque gains then factory. Not ridiculous (ie. A similar factory grind cam shaft was searched out and used)..., Just the use of better mechanical components in key areas of the engine build that are available today. The original C-6 was rebuilt with an added shift kit. An upgraded torque converter was installed as well. Keep in mind that the factory already upgraded this particular trans ie. the addition of the cast iron tail shaft which in my mind indicates that the engineer’s were aware of the additional stresses on the drive line. .. The car also came with the upgraded 9” trac-lok rear end. I know for a fact based on my observation’s of my car during initial tear down, that the car was driven very, very hard all its previous life. It was still solid, no abnormal kinks other then those caused by driver error and the use of air shocks... My point: If the factory built and released these car’s with almost 400 hp and 500 ft/lbs. (truer #’s than as advertised), then additional structural reinforcements are really not necessary on a factory restored car... Of course this is fully contingent upon a sound body to start with.

 
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Make sure the plate under the exhaust is still there-very important on verts. this plus the subframe connectors are enough unless you get to doing some significant power upgrades.

Roll bars don't add much chassis rigidity until you get to the 8 point versions and full cages, but they make street driving potentially dangerous as in a collision the bar is the hardest thing in the area and will crack your head open like a pecan.

Welcome to the forum where we don't want you to crack your head open like a pecan! (at least not yet)

 

japrine

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I was actually going to start a new thread because all info I could find on monte carlo bars are a few years old. It seems that the consensus is that the straight ones that are sold for our cars do not work as they will hit the distributor. Can anybody tell me for sure if a curved one from a different year such as 1970 fit a 1971 engine bay?

 

jimchil

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1973 blue Convertible 351 Windsor modified. Automatic.
[url=https://ibb.co/ZWtyVsL][img]https://i.ibb.co/Pw3BNpm/20190517-080704.jpg[/img][/url]

[url=https://ibb.co/6sdD8Vj][img]https://i.ibb.co/MNXPfWF/20190517-080704.jpg[/img][/url]
I was actually going to start a new thread because all info I could find on monte carlo bars are a few years old. It seems that the consensus is that the straight ones that are sold for our cars do not work as they will hit the distributor. Can anybody tell me for sure if a curved one from a different year such as 1970 fit a 1971 engine bay?
 

jimchil

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1973 blue Convertible 351 Windsor modified. Automatic.
[url=https://ibb.co/ZWtyVsL][img]https://i.ibb.co/Pw3BNpm/20190517-080704.jpg[/img][/url]

[url=https://ibb.co/6sdD8Vj][img]https://i.ibb.co/MNXPfWF/20190517-080704.jpg[/img][/url]
Thanks to everyone for their thoughts. A race car builder told me my Mustang wasn't really designed to be a convertible. And his friend said something worse so I panicked. I think I will stay with just the subframe connectors and a curved monte carlo bar if I can find one. I always read good reviews for Global West. Car has a modified 351 Windsor guessing 400 hp. But I would like it to corner as well as its smaller cousins. I have never had a convertible before and looking forward to it. Waiting for tags from DMV after nonop. It has a black top that has a couple of small places coming apart that need repair. If it can't be repaired what do you all think if I changed it to white? Has blue interior. Will post photos when I have some. It is well optioned. Power steering, power windows, power top. None of which currently work. But I did pick up an 8 track to install and some Beach Boys to relive my youth. Ha. Thank you folks. Hey Iowa, ever hear of Cherokee?

 

jimchil

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1973 blue Convertible 351 Windsor modified. Automatic.
[url=https://ibb.co/ZWtyVsL][img]https://i.ibb.co/Pw3BNpm/20190517-080704.jpg[/img][/url]

[url=https://ibb.co/6sdD8Vj][img]https://i.ibb.co/MNXPfWF/20190517-080704.jpg[/img][/url]
I was actually going to start a new thread because all info I could find on monte carlo bars are a few years old. It seems that the consensus is that the straight ones that are sold for our cars do not work as they will hit the distributor. Can anybody tell me for sure if a curved one from a different year such as 1970 fit a 1971 engine bay?
 
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No need for a mote carlo bar. The shock tower supports are the there already. Your race car buddy is wrong, don’t let him freak you out about this. Like others have said they built convertibles with a 429 torque monster from the factory. Now unless your engine is 600 hp or something like that, and you are going to race it, then maybe you would need one. Otherwise going with some subframe connectors will be just fine.

 
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As far as I know the 2015 Mustang is the first one to be specifically designed as a convertible from the start. https://www.forbes.com/sites/matthewdepaula/2014/03/31/the-ford-mustang-convertible-gets-major-improvements-for-2015/#30afd6c56d3f

The sub-frame connectors will do wonders for the car's handling, ride quality, and rattle reduction. In my opinion it is the first modification to improve handling on any unibody car of this vintage. Chuck

 
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Modified 1970 Mach 1 M-Code with a 351C 4v Manual

71-73 verts from the factory have the addition of a inner rocker and floor pan reinforcement plates with a heavy plate across the tunnel to address body twist, none of which are present on a hardtop. Adding Subframe connectors will do little for torque or twist in a vert, but they will help greatly with mid section body flex particularly when the top is down. Some might disagree but as a long time vert owner that's my opinion. I have both a 73 and a 70 and the engine bay is wider on 71-73 so they take different Monty carlo bars. I agree with others the stock shock towers are reinforced and cowl braces are sufficient for street builds. The shock towers on earlier years, with exception of factory big block cars, were not reinforced and notorious for cracking.

 
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