7 1/4 question

[MassDart]

So as it turns out, my 67 Dart 270 has a 7 1/4 SG.

How rare are these? How durable? More durable than the non posi unit?

I have generally used Redline Heavy Shockproof in rear diffs on cars. Will that be okay for the SG, or should I use something different? Should I stay away from synthetics?

Thanks,

Doug

 

[RustyRatRod]

Synthetic is good. It won't hurt it. Unless it has LSD additive in it, you'll need to add some. I like the Ford friction modifier best. The sure grip unit equipped 7.25 rears are much stronger than the open ones.

And yes, 7.25 sure grips are pretty scarce and so are any service parts. Good luck with it.

 

[azaustin]

I have two 7.25 SG’s for my ‘65 GoGo clone coupe and convertible. The main reason I want to use them is to keep the cars original. I’m interested in your comment that SG equipped rears are much stronger than the open ones. I thought they were just the same rear end with a SG unit added. Do they have better bearings or other parts? Just curious. The 7.25 in the ‘65 GoGo I had in high school took a year of abuse (including many runs at a local drag strip with “cheater slicks” mounted on steel 14” rims) and never gave me any trouble. I can’t say the same for the Auburn Clutch that came in it.

 

[Scody21]

I’m using Red Line 75/90 gear oil in my 8.75 suregrip. This already have the slip modifier in it so no need to add.