Rear coil over questions
 

I am looking for some advice on my 63 nova project. The rear is a nine inch with a three link and a watts link. Currently the top shock mount bar is not mounted. I am looking to purchase them now and don't know what I should go with. Is a taller or shorter shock better? What spring rate to go with? I am not sure of the weight currently but I would like a good starting point. The floor will have to be built so I can mount the upper mounts at almost any height. I am thinking some brand of single adjustable coilover maybe ridetech? Or qa1? The car will be just a low, big wheeled, big braked, mean street car no track days planned. Any opinions would be great.
Thanks in advance.

Also they will be mounted about 20 degrees from vertical.

Typical setups manufacturers are using is 5" stroke shocks out back vertical. With 20* tilt, you could stay with a 5" and keep more travel which is always better

20 degrees is an awful lot. Bring it more upright. 10-11 degrees max

good point.

Thanks for the input guys. I can mount them pretty close to vertical. I geuss in my head I figured mounting the lower mounts the furthest out on the axle would be the best. I could mount the lower mounts inboard of the three link mounts. Do you guys have a good starting point as far as spring rate? I am thinking of going with a ridetech or qa1 that uses a 10 or 12 inch spring.
Thanks again

spring rate is difficult to guess. you really need to weigh it and use the spring rate calculator located here:
http://www.ridetech.com/tech/spring-rate-calculator/

However, if it's set up similarly to our 4-link locations you'll likely use somewhere between 175-300# springs.