by megavega » Tue Nov 01, 2011 4:03 pm
Most any street car guy is never gonna "twist the body" or need this. Mostly because the car will just spin street tires and never really stress the chassis from the engine. I can see this needed when you start to use slicks and make trips to the track with 450+ hp hi torq.engines. A "rollcage", meaning one with halo and windshield bars will do far more to stiffen up the chassis then a peice of tubing just welded to the pinchweld seam. Think about what your doing, your adding tubing the length of the floorpan on the outer most rocker sill, this merely makes it harder to bend the car in half from front to back in case you park it on a large anthill in the middle of the floor.
That does nothing to keep the car from twisting, and by twisting I am talking about what a engine does to a chassis from torq. the left tries to lift while trying to smash down the right side. if no crossmembers are put into this tubing down the sides its not doing anything to keep from twisitng, your just adding more weight.
Simply lay 2 pencils side by side in front of you, pointing lengthwise away from you. now pick up the end of one, no effort to do so. Now lay 1 more pencil at the front and 1 at the back, now lift up on original pencil, you have more weight there because the crossmember is gonna make it not twist so easy. With this ladder type frame you incorporate into the vega floor you must weld the floor and everything that touches it to get the benefit from tying it all together. To me to get any use of this you would need to section the floor, lay your ladder looking frame in and weld the pans/brackets all together as 1 unit, tying it all into the rocker panels.
The rollcage adds more strength because its a series of triangles,which is the base strength of any race car chassis. It ties in the unibody from front to rear,side to side. if you use sill bars these act exactly the same as the tubing your putting underneath but dont take up any room in a compact chassis.
There is no "subframe" to connect on a h body the entire floor is the frame, unlike a camaro or nova which had a sub front and you tied into the rear unibody, the vega/monza,etc is all 1 part sheetmetal stamping, the rockers are multi wall and strong. The foam filling will help with the new technology foam out for just that, but youll never put anything in or under that car of more benfit strengthwise then a rollcage welded to plates to the rockers and side to side crossmembers.
I understand some people dont want the look of the cage or the bother of it but you might also not need anything either if you fall into street car territory, just a v8 in a vega doesnt mean it needs a frame added till you get into big power. This is just my observation/expeireance with running these cars on the drag strip with multiple engines,sbc-350,406, then to big block 427,468 all were used with transbrakes and slicks so I am sure I used harsher conditions then youll find cruising to your local hang out sat night..
1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....
1973 vega wagon-under the blue flame knife.