absolutely nothing if you live in an area with beautifully paved smooth roads. but for you and me living in slo where the roads are like @ss, 620s would rattle his teeth out of his head.

i was gonna get 620s until Tad made me realize how ****ty slo roads are, my car rattles enough as is lol

 

Nothing wrong with the 620s if you are building a race car they are very stiff. They still ride very very stiff on the street in my 65 and I have the extra weight of a Cleveland on top of them. I was able to soften up the ride a little bit without giving anything away with the addition of the IAS shocks. In my 67 which I am building in a similar vain as the 65 I am not using the 620s. I am simply putting the big block springs in and will trim to the height I want.

 

1" is plenty unless you are competing...

 

I seem to remember stock coils on 65-68 being 480 lb. Anyone know for sure?

Also, I helped restore a few gen 1 mustangs that had 3/4" sway bars. Was this a dealer option back then, or was it just an old standard size aftermarket part people used 20 and 30 years ago?

Just curious. I like Mustang history.

CP

 

You might even want to go with a 7/8" sway bar. You don't have enough weight in the front and with heavier springs, it will be fine.

 

I agree, GT springs (cut if needed), Shelby drop, and 7/8" or 15/16" front sway bar. Stiffer springs or a larger sway bar will make the front end of your light I6 car extremely stiff.

 

Mustangs Plus has 2 stock V8-application springs listed for the 65-66:
http://www.mustangsunlimited.com/ite...p?T1=CS8090+01
http://www.mustangsunlimited.com/ite...p?T1=GT2670+01

235 lbs./in and 480 lbs/in used on the Gt and Shelby Gt 350 models.

Does 235 sound a little soft to anyone else?

 

235 sounds like I6 springs. 480 is the GT spring rate, and I believe stock 289 springs were about 360

 

The vendor in the link lists the 235 coils as: "Application 1965-1966 289 w/ or w/o air"

That could be MU making a mistake or just marketing them to their own satisfaction. Or it could be correct. Either way, it doesn't sound like a sufficient stiffness for fast, bad roads. When you have a 289 2bbl with polyglass tires, no one is taking turns at high speeds so maybe that's why 235s seemed OK.

CP

 

I believe the factory GT sway bars were 13/16.