If I get a used big block 727 to learn to rebuild it myself, are there some years or original applications that are better for a performance trans?

Same question for valve bodies, because I know there is some change between 1971 and newer compared to earlier. Does it makes a difference if the valve body is going to get a mod kit in it either way? Does it matter if it started out as a 904 valve body if its still going to be modified?

What is a fair price for a rebuildable core 727? If I buy a used valve body separate from the trans, what should I expect to pay? The prices I see on ebay vary so much I don't know to think.

Does it make a difference with the trans case or tail shaft housing if the car uses a factory floor console Slap Stick shifter? That didn't occur to me in my first list of questions.

Not sure about that last question. Am I confusing this with 4 speed trans extension housings that have different shifter mount locations for different body styles?

For a car application,stay away from the RV and 4wd casings. Most have a short or no tailstock at all.

Any B/RB 727 from 66 and newer are acceptable as cores for rebuild.
They have the slip yoke and rod actuated shifting (cable shift 65 and older).

Since you are going to rebuild the trans,you can install the part throttle 3-2 kickdown feature from any /6 or any 904/727 trans from the 70's-up
Use quality parts for the rebuild.
Be sure to match the convertor to your choice of cam and rear gears.
Hemi 727's came with 4 clutch bands,others had 3,so never hurts to throw an extra one in--again depending on what you are using the car for.

Another trick is install the lower first gear ratio from the 80's 999 trans found in 5TH Ave's and Diplomats for the quick take off in first gear.

The column or floor shift features are bolt on and not like the 4speed tailstock.

Others may chime in to add.
Hope this helps.

Yes, many trucks don't have ears on the bottom of the tail for the floorshift bracket.

The 904 valve body can be used in a 727 but the rear center attach bolt hole needs to be elongated.

Won't fit in the subject 727.

How would I be able to tell what the trans original application was? Is there something in the markings that would help identify one with 4 pinion planetaries instead of 3 pinion, for example, without having to tear into it first?

Make sure to use a 4 friction front drum. No need for 4 pinion planet. I currently run 3 pin planets in my 9.0@3340lb car. 600+ passes 6 years. You'll strip the planet carrier before you hurt a pinion.
Doug

The part number stamped in the drivers side pan rail will tell the application, post the numbers here.

Since most 727's are 40+ years old, it's anybody's guess what you'll find inside.

I have had the roll pins come out on the pinions before. I like to use 4 pinion if I have one on hand. 4 clutches minimum in front.