small bolt disc's on a 74?

http://www.forabodiesonly.com/mopar/showthread.php?t=323645

You can use a factory 65-72 Kelsey Hayes disc brake set up to do that type of conversion, to stay small bolt pattern.

You are working with a 74, with 6 cylinder that has Drum brakes on it, I guess.
That would be 4 inch, small bolt pattern.

You would need to change your upper control arms, to 62-72 small ball joint upper control arms to use these brakes, and use 65-72 DISC Brake lower ball joints for the swap.

UCA's are easy to come by in America, but in your country, not so.
But easily findable by advertising in the Wanted section.
Ball joints are obtainable from any vendor, parts store.

Something for you to think about.