G-Body Frame Sag

[rmccubbin]

I've read I need to have this checked for before I start putting my car back together, namely, putting the body back on the frame. Is this correct? The reason I ask is because I called a local body shop to talk to them about this but they said they correct frame imperfections with the body "on" and I should do this afterwards. What's the truth? Is frame sag at the cradle a big deal? Thanks guys.

[mongoose]

are you not boxing in the frame?

[rmccubbin]

I'm on the fence about that...still haven't decided whether or not putting a 4th wall in the open middle portion is really neccessary. The frame is 2/3 factory boxed. Opinons?

Is the boxing related to fixing engine cradle sag somehow? I don't follow .

[mongoose]

it will prevent the 'sag'........ and most other flexing..

theres nothing to be on the fence about boxing in the frame.... there is not one downside to doing it.

[rmccubbin]

Thanks for the reply Mongoose. So you recommend boxing, but I'm still at square one with the sag issue as far as having it checked before hand. My car had 250K miles on it before I tore it down...I guess I need to talk to a body man who knows what I am talking about and get them to check it out.

[GBodyGMachine]

Box it and notch it, you wont regret it, trust me. Then be sure you use poly body mounts.
Jeff

[jackfrost]

i thought frame sag was more of an issue w/ a-bodies than g-bodies. i think the engine cradle area is beefier on a g-body.

i would call frame shops or body shops and see what they say.

[rmccubbin]

i thought frame sag was more of an issue w/ a-bodies than g-bodies. i think the engine cradle area is beefier on a g-body.

i would call frame shops or body shops and see what they say.

That's the info I'm getting from other sources. Thanks Jack!

-Ryan Mc.

[BigBlockOlds]

it will prevent the 'sag'........ and most other flexing..

theres nothing to be on the fence about boxing in the frame.... there is not one downside to doing it.

Except that you'll need custom brake and fuel lines. But I agree, boxing the frame has made a huge difference in the rigidity on my car. It hasn't been on the road yet but you can tell when jacking the car up that the frame is flexing a lot less.

For the record, we put my car on a frame machine at the body shop to check it before pulling anything apart. With 200,000 miles on the car and 50,000 of those with the 455 up front, everything checked out spot on within factory spec.