I've got 4 JW ones and they are all nice and straight. I bought these due to the fact that they are accurate shape wise. Everyone says the ASC ones need 'finessing' to fit a jig. I've also heard the left and rights aren't the same profile in the front half.
On the other hand the JW rails are 3/16" or so narrower between the front and rear crossmember positions to allow for mounting boxing plates corner to corner for welding, bringing the width back to 2". That kinda says compulsory boxing.
The JW rails also include a smooth c-notch for the diff in the stamping.
On the other hand the JW rails are 3/16" or so narrower between the front and rear crossmember positions to allow for mounting boxing plates corner to corner for welding, bringing the width back to 2". That kinda says compulsory boxing.
The JW rails also include a smooth c-notch for the diff in the stamping.