Looks like 71 ebodies had a single spring or torsion rod to hold up the deck lid. Is it the same diameter as a 70 or 72 to 74 ebody that has a pair rather than a single torsion rod?

I thought all spoiler cars got two torsion springs?

I know my 72 single torsion bar cannot lift the decklid with an AAR spoiler. Real 70 AARs came with 2 torsion springs.

the torsion can be adjusted setting it in another hole for more torsion. My Charger ( no spoiler ) got two springs, one attached on each side. Maybe due the bigger lid ?

A friend of mine molded the trunk lid on his 71 Charger like making somehow a ramp to work like a spoiler with bondo, and never took care of the added weight... allways had to use something to keep the trunk lid open untill I told him to increase the torsion giving one extra hole on each side... problem solved

71 Challenger Did only have one spring rod. I think it may have been just a little bit larger but not much. I think it was how it was positioned that made it work. It must have not worked to well as they returned to 2 rods after 71

Thats what I'm seeing as I research this. Doesn't look like the supports that hold the spring have any provision for using two springs on a 71 model & I'm pretty sure the single is a larger diameter which means the plastic guide the deck lid hinge rides on is probably different as well?

I think the cars that left with one spring are only setup for one spring, at least my 72 is. I cannot upgrade to dual torsion springs. Loading the single bar enough to keep the decklid up [barely] with a spoiler caused the decklid to twist when shut. For now, I removed the spring until I can get to a strut of some sort.

71-4 used a thicker single rod verses the 70 thinner 2 rods.
Challenger are longer than Cuda.
Hardtop is different than convertible.
70 is different than 71-4.
So there are several different E-body rods.
Also the 71-4 single rod will hold a wing when adjusted up tighter.

The vast majority of 71s have the single larger diameter torsion spring. Very late cars went back to the two spring design.

So 72-4 had 2 rods? Haven't messed with those years much, mainly just 70-1.

Yes they went back to 2 rods

what I'm saying

Well alrighty then.

3570335 27 body style 1971 Challenger
3570334 23 body style 1971 Challenger

3570333 27 body style 1971 Barracuda
3570332 23 body style 1971 Barracuda

2963360-1 23 body style 1970 Challenger
2864302-3 27 body style 1970 Challenger

2963358-9 23 body style 1970 Barracuda
2964300-1 27 body style 1970 Barracuda

Two bars on a 1970, one bar on 1971