I've been looking at nearly every vendor of disc brake conversion kits and they range from a 3/4" offset to a zero offset, depending upon who they're being sourced from. On the one hand, even the 3/4 offset may not be a problem if you're not running great big tires, but if you're concerned, I'd definitely consider either 1/8" or zero offset. Also, there are some really cheap disc brake conversion kits out there and I'm certain they are from China. While this MAY not be a problem, do you want to bet the car or maybe even your life on it?? I just ordered tubular upper A arms for my
62 and went top shelf for that very reason. Paid nearly double what I could have bought them for but they're American made and quality! Here's another issue you may get into....don't know what you're trying to do but if you're converting from manual to power steering, you'll never get the 4-6 degree positive caster required by the new steering set up without changing the upper A arms. The factory stamped steel arms are plenty strong, they just can't be adjusted to get more than about one degree caster. Caster is the "angle" of the wheel center line from front to back. Positive caster tilts that center line back so that after a turn the wheels want to come back to straight and not tend to wander. These "B" body cars didn't handle great when new and with bigger wheels, lower suspension, dropped spindles and the possible addition of power steering, things get really goofy. A heavy duty stabilizer bar is another good addition, helping to prevent body roll on turns. I think the factory bar is only 7/8" diameter as opposed to 1" or even 1-1/8". This means less twist, less roll. CPP is probably your best bet for quality. A bit more expensive than some but I think you're buying quality stuff. Been a real learning curve for me!!! Get it all figured out before you plunk down your hard earned $$.