HELP! 11.75" Disc Conversion - Bearings, Seals Etc

I wouldn't say sliders are better or pin type are better... I can tell you I find the pin type quieter but the pads are a little more expensive most likely because they were not in production as long (around 73 to 78 I think) and the slider type were used over many more years (73 to 88 I think) and are easy to find

*The larger 11.75 brakes were available 76 to 81 I believe.

You asked about the calipers themselves... there is no difference in calipers, they are either pin or slider type, they will fit the appropriate caliper bracket. now there are differences in the slider callipers over the years between some body models and its to do with how and where the flex hose attaches to it.

As you said your doing the work to a 69 Cuda, I think asking for the 74 ABody callipers may be your best bet and not the later calipers though I cannot say 100% I'm also not sure what flex hoses will work for you either sorry but apparently they can be custom made to fit easily enough.

Oh the other consideration in flex hoses may be if you have a sway bar... if you do you may have the calliper on the 'back' of the spindle. I know I know that's not a good description but sway bar, disk brake Interference-1965 barracuda

Hope this all helps and not hinders