[Skip Fix]

OK guys I've read someplaces to wait and weld in the rollbar/cage with the springs you are going to run. But picking springs for vehicle weight will change after the cage is in. So does it really matter?

[warriors revenge]

where ever you read that you should never read anything again! use common sense and think is there anything that sounds right about that? put the bar/cage in the car where ever you are going to put it, and weld it in. i have never had to change springs after i have installed a roll bar/cage. the weight is in the center of the car, and gets divided between all 4 springs.

[Skip Fix]

Warrior what I read was that the springs may tweak the body slightly so weld once you get your correct springs so it's not preloaded welding it in. But I don't know how much weight the cage/roll bar (or different motor/tranny) will add to order springs for the correct weight.

3250 with a iron head SBC , iron scattershield and ST-10 tranny. Getting E head IA2 with TH400 and just a little interior to not look so gutted.

[screamingchief]

If the car/chassis is straight & level to begin with,and the bar is welded in then,I cant see the change to another spring changing that relationship very much either.

Ask yourself this,are full on tube chassis welded with the car sitting on the suspension?

So then ask yourself this,why dont they suffer issues when the chassis is assembled and the car is completed and the suspension assembled.

And dont mislead yourself,sure the tube chassis is stiffer,but it's not totally rigid by any means,there is flex in almost all chassis,just more in some than others.

If you got the SF connectors and subframe mounts and the bulk of the suspension other than the springs as you plan to run the car,I'd say weld the bar/cage in.

JMO.

[warriors revenge]

if you are that concerned about it, place jack stands under the frame, with the weight off the suspension. then weld your roll bar or cage in. if your chassis flexes because of spring pressure, you are going to have bigger problems than that!

kal
www.xtremefabrication.com
262-968-2514

[Skip Fix]

Well that was what I thought too.

So if you have a cage with a bar at the bottom still need subframe connectors?

[David Holmberg]

Skip, Scott Rex never had sub frame connectors in his 70 TA, just a roll bar.

However, I'd still put them in, along with the cage and lower bar. JMHO.

[mikeb]

Originally Posted by Skip Fix

Well that was what I thought too.

So if you have a cage with a bar at the bottom still need subframe connectors?

Yes; it is illegal to weld the cage thru the floor to a front subframe on a car without a full frame; the cage simply welds to the floorpan. So the cage does not really add any direct integrity between the body and the subframe. You will still need subframe connectors.

A cage does stiffen up the car quite a bit. I can now jack up one side in the front and lift the same side rear tire off the ground, while still being able to open and close the door.

[Region Warrior]

Originally Posted by Skip Fix

Well that was what I thought too.

So if you have a cage with a bar at the bottom still need subframe connectors?

Our local chassis builder runs the rear down bars all the way back to the frame rail just in front of tail lamps.

Some run the rear bars done near the shock mounts.

I would put'm in either way.
Ties everything together.

[Skip Fix]

I was thinking all the way back and per NHRA to the shock mount area.

So anyone have a guess to weight change with motor /tranny swap?

[warriors revenge]

on a subframe car, the bar/cage is supposed to tie into the rockers of the car, not just the floor. on a bar with a lower bar? i assume your talking about a rocker bar? you should have subframe connectors in the car, even before you put a bar/cage in it! as for the bars going to the back of the trunk? what is that going to do for you? the stress is put on the chassis where it is held up by the shock/spring, and where the front of the rear suspension mount is (very simplified version) the frame rails from the shock/spring mount back, are just holding the trunk pan up, and a place to mount the rear bumper!

kal
www.xtremefabrication.com

[ponjohn]

My s/f connectors are simply CM tube welded to plates tha connect the two seperate "frames". Plus the cage.

[rattus]

The body, subframes, etc. all have factory specified dimensional relationships that are independent of suspension components. These dimensions (available in a GM repair manual) should be checked with subframe rails and rocker panels level (front to back and side to side as depicted in factory manual diagrams) and corrected if off by > 3/8" before the cage is welded into place. This ensures that everything is square and in the correct relation to everything else. In other words you want the subframes and body to all be level and within factory spec. as you weld in the cage. This way the cage will help everything stay where it is supposed to be.

[92GA]

You should have the car on jack stands, suspension unloaded. You should have the car level as possible, front to back and side to side. If you weld in the cage, and the car is crooked it will remain that way. You should incorparate a rear cross member now, to weld your cage to, and to make a rear shaft loop. The rear down bars should be directly over the shock mounting points. Buy a chassie book now before you start, so you won't have to do any cutting later. Makes for a lot less work, and costs.

[Skip Fix]

I know all the specifics of welding to a plate for a subframe car-6" plate etc..
Yes I was talking of a rocker bar.

I have subframe connectors on my T top TA and have been underwelmed at what they do. We even put a small tack weld on the front part to the subframe and it doesn't appear to even cracked in the slightest, and the car has had soem pretty hard launcehs for quite awhile. So I wasn't sure with a cage and rocker bar if it would even do anything.

I'll have a chassis guy weld it in , just wasn't sure what springs to have on it when it goes there.

[Region Warrior]

Originally Posted by warriors revenge

on a subframe car, the bar/cage is supposed to tie into the rockers of the car, not just the floor. on a bar with a lower bar? i assume your talking about a rocker bar? you should have subframe connectors in the car, even before you put a bar/cage in it! as for the bars going to the back of the trunk? what is that going to do for you? the stress is put on the chassis where it is held up by the shock/spring, and where the front of the rear suspension mount is (very simplified version) the frame rails from the shock/spring mount back, are just holding the trunk pan up, and a place to mount the rear bumper!

kal
www.xtremefabrication.com

Back to rear rails is what they rec for a minimum standard 6/8 pt(street/strip).
But also highly rec upr/lwr cross bars with down bars near shocks.

[StangTamer]

I know a good chassis guy www.jamesbchassisservices.com that will custom fab and install a cage for you up here in the Dallas area. He installed my mild steel cage and MikeB's cage, and does outstanding work for a very reasonable price. I plan on having a him fab me up a moly cage here pretty soon. I know it is a few hours away but it is well worth it IMO.

[tempest455]

My rear bars go through the trunk floor and attach to the rear frame rails on each side of the tank.

[mbr]

get the nhra rulebook and go to sfispec.com to get the build sheet. both will give u the exact info u need. s/f connectors are a must. i used them along with a basic cage and the gains were huge. install a crossmember bar first. it will be welded directly to the body. next is to do your rear roll bar. next is to run bars from the outer edge of the hoop to the rear subframe closest to the bumper. then u run a "x" from the hoop to the shock towers. if u are going to go fast down the road do the cage now. the roll bar is 1 3/4" were a cage is 1 5/8". all weight adds up down the road. if u really want to do it the right way cut out the oe rear subrame and get the good 2x3 rear bars with subframe connectors. then u will have a really good piece for down the road. hope this helps. mike