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sub frame connectors

11K views 14 replies 9 participants last post by  Monk 
#1 ·
Hi, new guy here. Got a 72 Nova that I am replacing all of the metal on the car, at least that did not fall off as rust. I am interested in tying in the sub frames and there was a segment on Muscle car, Spike TV and can not get to the segment on this. oes anybody out there have a link on how this is done?
Thanks, Greg
 
#2 ·
Usually the instructions come with the kit. They give you the option of just bolting it in (not a good idea) or fully welding. On the better kits they move the front spring eye inboard to give additional room for rear meats. Then you use a bent rear spring hangers on the back of the spring to finish moving the spring inboard. If you are planning on doing any serious street/strip running and have even a wild hair of an idea that you might be putting in a roll bar later, I would suggest investing $20 in the video tape offered by Art Morrison called "Fast Track; Step by Step". It shows how to install each and every one of their products (from a full rear half, to only a four link, full cage or a roll bar, or anything in between) so that you will have an idea of how it is done and how easy it can be when done properly.


Big Dave
 
#4 ·
Did you see the program on Spike tv about the blue haired Nova last Sunday? He made his own and tied the connectors into the inside rocker panels. I tried to get to their web site but there was no info on just how he did it. Do you have any pics of just what you did as I am planning on doing the same thing. Greg
 
#5 ·
No I didnt see the show. Whattya mean they tied them into the rocker panels? Im not sure I fully understand that. Theres a few pics on my website of mine installed but I may I have a few other pics if theyd help. I made mine penetrate the rear floorboards and I welded them in almost the full length to the floorpans and they bolt onto the subframe. I did this for extra strength and so the subframe could still be removed.
 
#6 ·
If you look at the Art Morrison Tape they show how to construct a peripheral ladder frame to tie the high stress areas of the unibody together as they back halve the car and build a full cage inside of 28 minutes. It is a very informative tape for $20 bucks, even if you never hot rod the car and just restore one you can see how the factory glued it together as they cut out the various panels to run a full frame.


Big Dave
 
#7 ·
Speaking of subframe connectors, I want to install some without going through the rear floor (one reason is I just replaced the pans w/new). Anyone done this ? I was kind of picturing using square tube from the front subframe straight back to where it would contact the floor, then weld that to a piece of heavy (maybe 3/8 or 1/2") plate that is bent to follow the shapeof the floor. The plate would be about 6-8" wide and run under the floor, right up close to it. From there back, fab a bracket to bolt to the spring mount. Any ideas ?

Hey gferguson, mine's a 68 probably in the same shape as yours, I'm doing the same thing. It'll be a new car when done.
 
#9 ·
it is better to go through the floor with 2x3 square tube. Notch the tubing to go around the subframe snouts so you have a good 2"-3" of the 2x3 going past the end of the subframe snout so you have extra material to weld to for added strength. If installing an 8 point bar or even a cage use 2x3 square tube to locate the main hoop of the roll bar. Usually you will weld a piece of 2x3 from the connector you just made to the inside part of the rocker panel and it will come through the floor. This will be the mounting point on each side of the car to mount and weld in the main hoop of the rollbar. You will also want to follow the same practice up front where the door bars come down from the main hoop and attach to the floor by your feet. Use another 2x3 piece of square tube and weld it between the subframe and the inside part of the rocker. It will also come through the floor and give you a solid mounting point for those door bars. When mounting the 2x3 pieces to the inside part of the rocker panels it is a good idea to first weld in a piece of 6"x6" flat piece of steel about an 1/8" thick so you have a good mounting point for the pieces of 2"x3" square tube. Finally when you go to mount the back bars on an 8 point bar or cage make sure you go directly to the rear frame rail. You can reinforce that mounting point on the rear frame rail with some more 1/8" flat plate. I suggest cutting a slice down each side ofthe stock frame rail through the trunk and then bending a piece of that 6"x6" flat plate to fit over top and down each side of the frame rail. This will give a strong mounting point to weld the back bars too. Weld the slices up to the plate to finish it off. I see too many people just welding the 6"x6" plates to the floor pans and then welding the roll bar tubing to it..........bad idea. The car will still flex and if you have a bad enough wreck the floor pans will tear at those mounting points. When you add to the frame rails of the car and then weld the rollbar tubing to the frame peices it ties everything together....like a human's skeleton.

Sorry for so long winded but I see so many poorly built rollbars and stuff it kinda makes me sad to think that some poor guy probably paid someone $1000 or more to have a roll bar installed incorrectly.
 
#14 ·
it is better to go through the floor with 2x3 square tube. Notch the tubing to go around the subframe snouts so you have a good 2"-3" of the 2x3 going past the end of the subframe snout so you have extra material to weld to for added strength. If installing an 8 point bar or even a cage use 2x3 square tube to locate the main hoop of the roll bar. Usually you will weld a piece of 2x3 from the connector you just made to the inside part of the rocker panel and it will come through the floor. This will be the mounting point on each side of the car to mount and weld in the main hoop of the rollbar. You will also want to follow the same practice up front where the door bars come down from the main hoop and attach to the floor by your feet. Use another 2x3 piece of square tube and weld it between the subframe and the inside part of the rocker. It will also come through the floor and give you a solid mounting point for those door bars. When mounting the 2x3 pieces to the inside part of the rocker panels it is a good idea to first weld in a piece of 6"x6" flat piece of steel about an 1/8" thick so you have a good mounting point for the pieces of 2"x3" square tube. Finally when you go to mount the back bars on an 8 point bar or cage make sure you go directly to the rear frame rail. You can reinforce that mounting point on the rear frame rail with some more 1/8" flat plate. I suggest cutting a slice down each side ofthe stock frame rail through the trunk and then bending a piece of that 6"x6" flat plate to fit over top and down each side of the frame rail. This will give a strong mounting point to weld the back bars too. Weld the slices up to the plate to finish it off. I see too many people just welding the 6"x6" plates to the floor pans and then welding the roll bar tubing to it..........bad idea. The car will still flex and if you have a bad enough wreck the floor pans will tear at those mounting points. When you add to the frame rails of the car and then weld the rollbar tubing to the frame peices it ties everything together....like a human's skeleton.

Sorry for so long winded but I see so many poorly built rollbars and stuff it kinda makes me sad to think that some poor guy probably paid someone $1000 or more to have a roll bar installed incorrectly.
Great post. If you have pictures of this send them to me marlin_nut@yahoo.com Thanks! :thumbsup:
 
#10 ·
Unless your going fast enough that the track you race at requires a roll bar your looking at a lot of dead wieght. I know some of the guys here know the break over points for the big national organizations. You also have to think about it realistically. For instance while my engine design so far would probably get me into roll cage territory I am not tubbing and other than classic slapper bars for traction I'm going to be lucky to put my car into mid 12's. The torque I'll be producing is saying weld in sub frame connectors and solid subframe bushings, but the speed I'll get to says the roll cage is dead wieght (Unless I crash then I might not be calling it dead wieght). Getting a car into roll cage territory takes a lot of work and money. Then tuning once you get it to the track. I don't plan on running slicks on my car ever, but if I did I know I would have to be gentle on the clutch since the Pontiac 455 is known to be a torque monster and between only subframe connectors and an 8.5" ten bolt with 3.73 gears if it hooks in first the forces that body are going to see will result in something I am not building it for.
 
#11 ·
I made my own set at work and saved me some coin. I welded mine in, and if you want a really slick look, I cut a notch in the floor pan of the rear, and welded then to the floor as well as the frame. They only stick up about 3/8 of an inch or so and you can't notice it with the carpet. The side profile is sweet tho because most bought ones contour around the pan and can be seen from the side a mile away. If you want pics from underneath, let me know.
 
#13 ·
Thats what I did too, 7t. But I welded in a strip of 1" angle iron along both sides to weld to the floor and the SFCs down the full length. Youre right, it barely sticks up through the floor, but it makes it SO much stronger and helps with clearance and the profile :thumbsup: Shoot me some pics of yours too, 7t, if ya dont mind CDJr@bellsouth.net Thanky!
 
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