Howdy,
Looking at redoing some of the front end of my '70 240z.

A few questions have come up. 
Should I replace the bushing in the lower control arm? A 49yr old car, it seems like a smart idea.

Should I use the stock one, or use a urethane version? Advantage or disadvantage?
Also, what is the the difference in the steering knuckle between an early 240 and later 240? I have seen a different ball joint offered, but not sure how to tell the difference between the two?

Thanks
Bob

OE-style rubber bushings are generally best for street cars, poly-type bushings are best for track cars.  Rubber bushings provide compliance in the suspension so that harsh impacts are absorbed and  not transmitted directly into the body.  They also provide a small amount of flex that is not wanted in a track car where the suspension must respond immediately and consistently to driver inputs.  With poly bushings the ride is very tightly controlled and more harsh.  I initially installed poly bushings with my resto, did not like the ride quality and immediately swapped everything out to rubber.  Some OE/OEM rubber bushings are NLA so poly is the only choice - the steering rack is a typical example.

The online catalog shows a change in the steering knuckle and ball joint beginning with build date 7007.  I think the ball joint size was increased for durability.  If your car is prior to this date, you'll need to locate a pair of steering knuckles from a later car to fit the currently available ball joints.  Here's the link to the catalog reference:

http://www.carpartsmanual.com/datsun/Z-1969-1978/axle/front-axle

Hope this helps.

I'm restoring a 73 240 and interested to know how important it is to replace that lower control arm bushing? Or what's the best way to determine if it needs replacing?

 

Thanks

It needs replacing, unless the car has been restored at some time it will be worn.

56 minutes ago, timZ said:

I'm restoring a 73 240 and interested to know how important it is to replace that lower control arm bushing? Or what's the best way to determine if it needs replacing?

 

Thanks

At $12.14 each from Courtesy (plus shipping to you) how can you not do it?  Aftermarket is even less at Rockauto.

https://www.courtesyparts.com/oem-parts/nissan-bushing-link-54535e4100

21 hours ago, jfa.series1 said:

At $12.14 each from Courtesy (plus shipping to you) how can you not do it?  Aftermarket is even less at Rockauto.

https://www.courtesyparts.com/oem-parts/nissan-bushing-link-54535e4100

Thanks for the advice and link!