Can 71-72 Springs be put on a 73 B body?

[drobertson]

So... I'm gonna re-do the whole rear end in my '73 Charger. I picked up an 8.75 (741 case) from a 72' plymouth b body. My old springs have sagged further than I'd like, so I'd like to replace them. The problem is that I cannot seem to find 73-74 Springs at a reasonable price, whereas the 71-72 springs are more common and affordable. What would need done to put earlier springs on my Charger? Any recommendations?

 

[YY1]

Eliminate the "iso-comp" mount.

Either buy shock plates, or weld a thick washer in the ones you have, and get a standard center bolt.

That's an oversimplification, but that's the meat and potatoes.

Pretty common mod.

 

[Bruzilla]

There are two issues in play. The first is the iso-comp mounts YY1 mentioned. The second is what type of spring eyes you have. 1973 had two types, round and oval. If your front ones are round, you're okay. If they are oval, your springs will be slightly shorter, but about .75 inches, and you'll need to replace the front hangers to accommodate that. I would suggest using the Mopar Performance hangers for the 68-70 B bodies. They are long and you can drill a hole 3/4" back if you need to. Or, you can find a set of OEM hangers, but that's usually harder.

 

[drobertson]

There are two issues in play. The first is the iso-comp mounts YY1 mentioned. The second is what type of spring eyes you have. 1973 had two types, round and oval. If your front ones are round, you're okay. If they are oval, your springs will be slightly shorter, but about .75 inches, and you'll need to replace the front hangers to accommodate that. I would suggest using the Mopar Performance hangers for the 68-70 B bodies. They are long and you can drill a hole 3/4" back if you need to. Or, you can find a set of OEM hangers, but that's usually harder.

I will check and see what spring mounts I have. I sure hope they're the round ones!

 

[drobertson]

Eliminate the "iso-comp" mount.

Either buy shock plates, or weld a thick washer in the ones you have, and get a standard center bolt.

That's an oversimplification, but that's the meat and potatoes.

Pretty common mod.

What exactly is an iso-comp mount? I've never heard of them. Does anybody have pictures?

 

[Nacho-RT74]

Diagram I made long time ago, non iso vs iso assembly. althouught the pedestals height diff is not prooved, but found a problem trying to fit 71/72 modified rear sway bar plates on to my 74 Charger, that COULD BE related to a diff on this piece

 

[Nacho-RT74]

Also 71/72 springs got 5/16" stud guide, and 73/74 got 3/8" stud guide PLUS a bushing ( not shown on diagram ) to fit into an isolator recession

 

[Nacho-RT74]