Leaf Springs, Coils & Shocks

palerider94

Member
Feb 21, 2006
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Planning on changing leaf springs, front coil and shocks all around on my 1970 v8. planning on going with 4 leaf and stock coils. Not interested in lowering - low enough and like to have smoother ride than stiffer performance. I plan on replacing shackles. What is the advantage of going with polyurethane - over rubber?
 
better handling because of less deflection. if you're more worried about ride comfort then skip the poly bushings. personally i only use them on the rear springs and the sway bars anyway. you might check out a set of Opentrackers roller spring perches for the front, they will not only improve the handling a great deal they also soften the ride a good bit as well, since they are a full roller design they won't bind like the stock rubber bushed spring perches allowing the front suspension to follow the bumps in the road better.
 
Thanks for the tips on 4 1/2 leaf spring and roller perches will look at both - starting to add up $. Also, will use rubber bushings. What about 620# coils - suppose to drop an inch. Would this stiffen the ride up too much. Heard it should improve handling but again looking for a smooth ride. Trying to strike a good balance. Also, any suggestion on shocks - reasonably price but good?
 
the progressive rate springs would be nice especially with the roller perches however the 620 1" drop springs should ride fine and if you go with the roller perches any harshness that could come from the springs will be all but eliminated. something else to consider is that the 70 cars are much bigger and heavier than the earlier cars and can actually use a stiffer spring up front. i actualy run a 750lb front coil and don't find them to be a bit harsh. my car has a 351w with ac and power steering so it has a lot of weight on the front end which is probably why my car does't feel harsh
 
palerider94 said:
where do you find the progressive rate springs? I'm not familiar with the term.

We have had good luck putting KYB shocks up front and the Grab-A-Track shock in the rear on the street driven cars we build kits for. The KYB is a bit too stiff for the rear. The Grab-A-Track shock is made by Monore and isn't as stiff as the KYB. We have the progressive rate springs on our web site. I agree with bnickel that the 620 front coil/roller perch combo would be a good choice for your car. The 620's are really a 560-580lb spring.

John
 
Here is what i'm going for based on advice above - let me know if I'm missing something. Again look for best compromise between ride and performance, street driven only. 302 with c/4 auto. thanks for the help.

1. Open Tracker Roller Perches
2. 620# Coils
3. Export Brace
4. 4/12 leaf sring standard eye
5. Rubber busing and shackle kit
6. KYB shock up front
7. Grab A Track shocks in back

Also any recommendations on shocks kyb and grab a track make different kinds. Again thansk for all the help.
 
that all looks good. as far as the shocks go, you could probably just use standard parts store replacements if you want, just get the gas charged units. monroe matic plus or gabriel red ryders would be fine. or if you just want to order from mustangs plus the kyb GR-2 is a good shock that's not near as stiff as the kyb gas-adjust
 
Just installed the 4.5 leafs and grabatrack shocks. Very nice combination stiffer ride but took over some bad bumps just to see how it would react and not bone jarring. Thanks for a good recommendation. Looking forward to doing front end if it makes as much difference as the rear - should be a fine ride.