Classic Winnebagos & Vintage RVs

I'm looking to buy a 68-74 Winnebago with the "eyebrows" for restoration.
In first post here, it looks like parts wont be an issue.
Is there a rundown on changes through those years? Things like disc front brakes in 73 or 74. Any other changes to the brakes, axles, steering, etc?
Also any "good" and "bad" years or features I should be aware of?
And do even these smaller units really weigh 10K lbs?

I will say this simply.  You want the 73 and later M300 (also known as RM300) chassis with front disc brakes.  The earlier M300 and M375 chassis can be difficult to find parts for at this point in time.  The later chassis will also have the 440-3 vice the 413 engine

Thanks. I did notice the disk brake change up front but info on these is a bit scarce.
As for the motor, I would like to try to fit an 8.1/4L80e if I can fit the rear sump behind the center link.

73-74 M300 (RM300) Brake Info (http://dave78chieftain.com/M300_73-RM300.html)

Thanks, I found your site earlier here, good resource.