Small bolt front disc options for a 65 Valiant ?

Pirate Jack's "kit" is a 73+ disk set up that has the later rotors drilled 5x4". It's pretty obvious just looking at the parts, the upper ball joint adaptors in the kit confirms it. Mopar A Body Std Disc Brake Conversion Kit Wheel Kit Only (wheel pattern 5x4)

Which means 2 thing for certain- it will increase the track width of the car just like converting over to the stock 73+ BBP set up, and the center register of the rotor is larger than anything you'll find on a drum brake or even a KH disk car. Either one of those things would mean that your stock wheels probably won't fit, in combination it pretty much guarantees it. Unless you have aftermarket wheels that aren't hub-centric you'll be buying new wheels.

abodyjoe makes another good point, not sure what size lugs that kit will use. More than likely it's 1/2", but I don't know that for certain. Even if it is 7/16" you'd still have to overcome the diameter of the hub being larger (because of the larger bearings) and the track width change.

I see absolutely no reason to use the Pirate Jack kit. You'll need new wheels regardless, might as well bite the bullet and just go BBP compared to buying that kit. Wilwood has similar issues, the center register is too large for stock drum and KH disk wheels and they use 1/2" studs. I think Scarebird is the only kit that would actually let you keep the stock wheels, but I haven't used them so I wouldn't be able to confirm that.