1978 Mustang II in a 1939 Ford - Springs

I have a 1939 Ford with a 1978 Mustang II front end under it. The ride, while smoother than the original straight axle, is still to stiff for the wife on long trips. I have been told to change the front springs. I haven't found anyone who knows what the pound rating should be to get a smoother ride. In various parts magazines, I can replace the springs but there are a variety of pound ratings to choose from. Can anyone ***ist with the proper springs to use? Thanks in advance.

 

Most rods of you size and weight can get away with 4 cylinder springs. The correct way to gauge the spring rate would be to have the front half of the car weighed to find exactly how much spring you need. There are only about 4 or 5 springs available without having something custom made, and a good parts store,(Napa etc.) will have the book to tell you rates. Another way to tell if you have the correct spring is to check the lower control arms. If you haven't cut the springs, and they are full length, the arms should be flat to the ground. If they run down hill towards the tire, they are too much rate. If they run uphill towards the tire, they are too soft, or too short. It is ok to trim 1- 1 1/2 coils to help get the car to sit right, but the arms still need to be flat to the ground for everything to be correct.

 

according to the fatman catalog ... "***uming a small block V8 is used, light cars with the motor mounts 4 - 6 inches behind the axle centerline (33-34 fords, 34-35 chevys) usually need 4 cyl springs. heavier cars (1935-1954) usually have the engine mounted further forward and generally need V6 springs with 1/2 coil cut to level the arms"

if you cut the springs you have, they will get stiffer. measure the diameter of the spring and count how many coils there are. the next lower weight spring will only be slightly smaller with the same anount of coils. we changed out some springs a while back, went down from 500 to 450lb (?) and the diameter difference was hardly noticible.. had to measure cause to my eye they looked the same.

 

I Suggest 325 Lb Rate. I Can Help You Acquire Them.

 

Thanks one and all for your helpful info. I think I can now proceed to make the little woman happy. I had originally taken 1/2 wrap from the stock springs. This gave me the "look" I was after, lower arms are flat with a 3 degree (Fords anti-dive angle) tilt to the cradle when installed. Again - Thanks