Ford 9 Inch Questions

[scaotty]

I have a 75 280z that im swapping a 350 SBC into. At the moment Im rolling with the factory rear end, with future plans of swapping into a Gen I 300zx LSD. But Ive been offered a Ford 9inch rear end for free, and im curious how crazy of a job it is getting it into a 280z. I see from searching on here that it can be done, but I dont want to tackle something I can handle. Any info will be greatly appreciated.

[RebekahsZ]

Two popular ways:  ladder bars and 4-link.  Ladder bars require the least amount of fabrication, but usually leave the car with significantly reduced ground clearance (from the cars I have seen).  The 4-link is a much better suspension plan in terms of adjustability and being able to control traction.  The ladder bars sometimes promote wheelies, which while spectacular usually result in losing the race and often breaking the car if you come down too hard.  I have not done a 9-inch conversion, but likely will in the future.  To get educated answers, snoop the forums to look for drag racers and send them PMs (private messages).  Otherwise you will get a bunch of bench racing and debate instead of specific answers and good advice.  The biggest issue is that there isn't much to weld to in the unibody and some sort of bracing and subframing needs to happen-that's significant fabrication.

Edited August 27, 2014 by RebekahsZ

[SUNNY Z]

Best way to do it is a 4 link. This will require a back-half of the frame rails.  

 

Its all about your skill level. Have you ever done any fabrication?

[skirkland1980]

The nine inch would likely be too wide. A mustang 8.8 or pinto 8" would fit better.

[RebekahsZ]

I think just about any 9-inch or 8.8 would need to be narrowed.  If I understand correctly, there aren't many ratios available for the 8.8, whereas the 9 has a lot more options (?).  I guess it depends on what you want to do with the car.  When/if I do a conversion, it will be a 9 inch in order to be able to drop the whole center section and swap it without having to reset the R&P spacing.  I dunno, perhaps you don't have to do that with a gear change in the 8.8 (?)

[Six_Shooter]

Two popular ways:  ladder bars and 4-link.  Ladder bars require the least amount of fabrication, but usually leave the car with significantly reduced ground clearance (from the cars I have seen).  The 4-link is a much better suspension plan in terms of adjustability and being able to control traction.  The ladder bars sometimes promote wheelies, which while spectacular usually result in losing the race and often breaking the car if you come down too hard.  I have not done a 9-inch conversion, but likely will in the future.  To get educated answers, snoop the forums to look for drag racers and send them PMs (private messages).  Otherwise you will get a bunch of bench racing and debate instead of specific answers and good advice.  The biggest issue is that there isn't much to weld to in the unibody and some sort of bracing and subframing needs to happen-that's significant fabrication.

 

 

This has pretty much nailed it.

 

Look up terms like "back-halfing" (because people sometimes spell it this way :/ ), "back-halving", "tubbing", "solid axle conversion", and similar.

 

As far as whether to go through with it or not, it really depends on what you plan to do with the car. If I was building a drag car, or a car mainly used for straight line racing of some sort, then I would do a solid axle conversion. If it's mainly a street car with the occasional straight line sprint, I'd keep it IRS (Which is actually my plan, though the IRS will be quite different than the OEM design).

 

So figure out what you will really be doing with the car, and weigh the benefits of each type of suspension and how they will affect that use.

[Six_Shooter]

I think just about any 9-inch or 8.8 would need to be narrowed.  If I understand correctly, there aren't many ratios available for the 8.8, whereas the 9 has a lot more options (?).  I guess it depends on what you want to do with the car.  When/if I do a conversion, it will be a 9 inch in order to be able to drop the whole center section and swap it without having to reset the R&P spacing.  I dunno, perhaps you don't have to do that with a gear change in the 8.8 (?)

 

 

Yep, I don't know of any stock 9" or 8.8" that would fit directly under an S30 car, width wise. It's said to be easier to narrow a 9" than an 8.8, due to the way the actual axles are made, tapered vs straight. Aftermarket axles can be bought in just about any length needed for either rear end though, so unless you're trying to do it on a budget and use modified OEM parts, this point is almost moot.

 

Also while there may be a wider range in gear selection for the 9", that's not always a benefit. IIRC, the additional ratios of the 9" that the 8.8 doesn't (or didn't) have, would be ratios that I don't believe anybody with an S30 would ever truly use, like 4.88 and up, meant more for off road rigs, to turn the 36"+ tall tires. In the more common ranges I believe the 9" and 8.8 have the same available ratios, at least they used to have them available to both, I haven't kept up on the comparison game for gear sets in a long time. I know the 8.8 has ratios I would and can use.

[scaotty]

Thanks a lot everyone! Sounds like I would be biting off more than I can chew. Plus for what Im building this car for, it would make no sense. Thanks again everybody,