rene040269

So i am in the process of a full body off restomod of my '80 4 speed manual Vette and i am looking for ways to strengthen my chassis as much as possible.

Added all of the reinforcements as mentioned in the Chevy Power Book and some more, but i am looking at the big hole in the frame behind the batwing where every '79 or older Vette has a big solid crossmember welded between the two side rails.

With the introduction of the '80's all aluminium wide differential carrier the extra crossmember was deleted. Because the batwing is connected with rubber mounts it gives hardly any additional strength to the chassis, at least that is my opinion.

I am thinking about welding in a crossmember just behind the batwing supports for additional strength and stiffness.

What are your thoughts about this mod.

Is the rear compartment floor of an '80 model the same height height as compared to its older brothers? Meaning: if i weld in an extra crossmember on the same position as in <79 Vettes would that not interfere with the floor?

Thanks in advance

softwarejanitor

Why do you doubt the strength of your chassis so much? Are you running a > 500HP engine or something?

rene040269

Eeehh, no.

I am nut running 500 HP on this moment, actually i don't run at all because i am looking at a bare frame and a pile of parts right now. But a major upgrade in enginepower is certainly in the future and i don't want to take the car apart a second time. So now is the time to upgrade.

And even if i think the car on this moment will not push over 200 ponies (worn standard 33 year old chevy 350) i certainly don't think the frame is very stiff or rigid to begin with, or all the hundreds of topics about this issue were all wrong.

The question is if someone knows if the floor of the rear compartment of an '80-'82 Vette is different compared to a <'79 Vette?

If i weld in a <'79 crossmember behind the batwing will that interfere with the '80 floorplan?

bhays

Does anyone have 79 vs 80 photos handy to post?

rene040269

Well, this is an '80-'82 frame. Check the rear end, no crossmember behind the batwing/diff mounting points



This is a '79 and older frame with a solid crossmember in the rear:



The diff is mounted to a steel bar which is connected with rubber joints to the chassis, basically the same setup as a later batwing style.





I feel comfortable with this extra crossmember and want to add it to my '80 chassis, but without interference when i drop the body.

qwank

the batwing acts as that metal "crosmember" you are talking about. it's just as strong and a lot lighter.

rene040269

Well, given the fact that the alu batwing is suspended in rubber joints to the frame i don't think it will add much to the stiffness of the frame.

The same with the sombrero rubber joints from the '79 frame, but that type has a welded crossmember just behind it, which actually will do something to improve stiffness.

But the question is not why or if i would do it because that descision is made but if someone knows if the floors of the two models are different.

I will add this crossmember just as low underneath the frame rails as with a '79 frame but not would risc the body to touch it.

Any thoughts?