Question concerning fit of front brake rotors
I think that he is right Ian. 71 is different then your setup.
A mixture of 71 and 75 won't work. The 71 would be a Kelsey Hayes caliper with 4 pistons per caliper and the smaller wheel bolt pattern. The hub has 5 holes on a 4" diameter bolt circle with 7/16" diameter studs.
The 73-76 style has a single piston per caliper and the brake pads fit into machined grooves. The 73-76 style uses a larger upper ball joint than the 65-72 and the rotor has the larger bolt pattern. 5 holes on a 4-1/2" bolt circle with larger 1/2" diameter studs.
In either case, the caliper mounts to a cast iron bracket that bolts to the steering knuckle. (Chrysler calls them knuckles, not spindles) I'm pretty sure the rotor for 65-72's is 1" thick and it's thicker on the 73-76.
First step would be to pack the wheel bearings with grease. The larger bearing goes into the back side of the rotor and a grease seal is pressed into place over that. You can install them with a hammer iof you are careful and take your time. Put the rotor onto the shaft and fit the smaller bearing over the "spindle" and into the recess of the rotor,. Next is a special flat washer that has a "key" on the inside diameter. Next is the spindle "nut", then a cotter pin and then the dust cap.
If you have a shop manual just follow that but it sounds like you have a mixture of incompatible parts. You have to use all 65-72 parts or all 73-76 parts. If you have to make a choice, go with 73-76 to match the bolt pattern on the rear axle. That is assuming Chrysler followed the same timeline in your country regarding the brake change-over.
You really should post some pictures of exactly what you have! Surely if you cruise this site, you'll find enough pictures to show what you need to do.