Chassis Subframe Differences 71 vs. 72?

[71_bronze_gtx]

While searching for a good photo of a 71 undercarriage I came across an expired ebay listing for a 72 SSP. In pix of the bottom, I noticed that some structural boxing that is on my 71 GTX is not on this 318 72 SSP. I'm wondering if these were added for high performance engines to stiffen the chassis, or were they on all 71 cars and deleted for 1972?

[rr6pak]

While searching for a good photo of a 71 undercarriage I came across an expired ebay listing for a 72 SSP. In pix of the bottom, I noticed that some structural boxing that is on my 71 GTX is not on this 318 72 SSP. I'm wondering if these were added for high performance engines to stiffen the chassis, or were they on all 71 cars and deleted for 1972?

They are for high performance and are call "torque boxes" so the torque from the engine doesn't flex or twist the body. They're welded to the four corners of the under carriage. I installed them on my car

[71bird]

Sometimes even plane jane cars would get them and some cars just got them on one end of the car. If they had parts left over they would stick stuff on any car.

[71_bronze_gtx]

Thanks. As I suspected. In my case, the forward perch for the leaf springs is bolted to this "box". For this SSP in the pix, there must be tubing or channel subframe sections obscured by the lift pads which the perches are bolted to, which suggests the torque boxes are a substitute rather than add-on - at least in the rear. Hmm.

Dealing with rust inside these subframes is a challenge. Mine were previously undercoated, and it is peeling off. Can't get access to remove all the loose crap. I'm shooting in overdoses of Eastwood "Internal Frame Coating".

[rr6pak]

Thanks. As I suspected. In my case, the forward perch for the leaf springs is bolted to this "box". For this SSP in the pix, there must be tubing or channel subframe sections obscured by the lift pads which the perches are bolted to, which suggests the torque boxes are a substitute rather than add-on - at least in the rear. Hmm.

There are bolts, securing studs, on the forward section of the perch, that's how it is secured to that section. The torque boxes has a hole to put a socket and even your hand up in there to put nuts on the studs. The torque boxes are welded and closes this area up, making a "box" and stiffening it up. The forward section of the springs is in the same place as factory installed it. After you have the springs secured with the nuts in this hole, then you can put undercoating in there (if wanted to). It would be harder to remove undercoating from this area with the torque boxes installed, because it's closed or boxed. I'd have to look to see if I have a picture of mine in my computer to make it clearer.

[71_bronze_gtx]

That's OK - it's pretty clear to me - I've been under there looking at this stuff for a month. In the rear box on the passenger side, I looked inside with a borescope, then reached inside as best I could to scrape off loose undercoat, made a small hose attachment for my shop vac to suck out all the debris, masked off the perch mounting bolts, and filled that sucker up with Eastwood internal frame coating, along with the rest of the subframe members between wheel wells. No real access to the front torque box or transverse frames to scrape, so I just overdosed them with coating inside.

What got my attention in the 318 Satellite pix was the absence of the torque boxes and the fact that tubular subframe members were there instead. In the rear, they hold the perches, and in the front I suppose they stiffen the rocker structure where the fenders are bolted on.

[rr6pak]

That's OK - it's pretty clear to me - I've been under there looking at this stuff for a month. In the rear box on the passenger side, I looked inside with a borescope, then reached inside as best I could to scrape off loose undercoat, made a small hose attachment for my shop vac to suck out all the debris, masked off the perch mounting bolts, and filled that sucker up with Eastwood internal frame coating, along with the rest of the subframe members between wheel wells. No real access to the front torque box or transverse frames to scrape, so I just overdosed them with coating inside.

What got my attention in the 318 Satellite pix was the absence of the torque boxes and the fact that tubular subframe members were there instead. In the rear, they hold the perches, and in the front I suppose they stiffen the rocker structure where the fenders are bolted on.

As far as the front connectors, no access to inside if they're already put in. I've never seen tubular in the front, that's odd. A 318 don't need them IMHO and don't think they did. A 340 did for the AAR Cuda I think but could be wrong

[71_bronze_gtx]

It's hard to be certain from these pix, and I'm only assuming that they're tubular. Might be channel. You can see that something is there in the front and the rear. Maye the boxing was added right over top of what's already there rather than instead of. When I got back under my car for a better look at the rear ones, it does appear that there is double-walled structure where the perches bolt on. With all the scale and undercoat, I can't tell for sure, and I guess it doesn't really matter for what I'm doing. I was just curious. I have a "car buddy" acquaintance who did drop a built 440 into a '71 318 Satellite car. I doubt he did anything to beef up the chassis.

[71bird]

Maybe I can get a picture of mine in the rear. My car is black, so I don't know if a picture will turn out, but I'll try.

[rr6pak]

Maybe I can get a picture of mine in the rear. My car is black, so I don't know if a picture will turn out, but I'll try.

Don't know for sure if I have pictures of mine or not. I need to sort through them and post all what I ahve done to it.

BTW-It is double wall thickness where the perches are bolted to

[rr6pak]

It's hard to be certain from these pix, and I'm only assuming that they're tubular. Might be channel. You can see that something is there in the front and the rear. Maye the boxing was added right over top of what's already there rather than instead of. When I got back under my car for a better look at the rear ones, it does appear that there is double-walled structure where the perches bolt on. With all the scale and undercoat, I can't tell for sure, and I guess it doesn't really matter for what I'm doing. I was just curious. I have a "car buddy" acquaintance who did drop a built 440 into a '71 318 Satellite car. I doubt he did anything to beef up the chassis.

What motor is in it now? Is it original?

[71_bronze_gtx]

Assuming you're asking about my GTX, it's the original 440-4 with a big hydraulic lift cam (and nothing much else to help it breathe or even hold together at high RPM). Doesn't do a whole lot but sounds MEAN.

[rr6pak]

[71bird]

These are the best I can do. Also there are different companies that make these thins and they may look different. There is a year difference between 71/71 and older B body plates. This is the front.

[71bird]

Rear. I hope it helps. I didn't install them. These particular boxes didn't come with the lip around the access hole, so the body man made those lips cause they had them from the factory.