I have been trying to educate on the 727 Valve body. Seems like most of the internal parts were consistent year to year from the parts manual. 66 pretty much had one valve body part number for all models. 67-68 had a change in part # and you now had 2 basic versions one for HP and one for the others. Seems like the only part different was the transfer body (plate body). 69 the part number changed again and stayed same through 70-71. But some of the parts did change like the plate number. Not sure how that can happen, unless the plate was the same with just a part number change administratively.

Seems like the VB part number 21-139-4 was an assembly part and the only way to get the actual body. All the other individual parts are listed separate.

So was there any real difference, or was it primarily some lever parts that changed from 66 to 71. I realize the plate body has a difference between the HP and normal, but what about the main body itself?

I have one that was probably overheated and had gummed up and stuck the various valves. Not sure what it is from, but the main body has casting # 2892348 and looks like a late Dec 68 casting date. So I assume for a 69 trans. The plate body is the common LP 2801295. I assume the plate is the 2838043 which is common between HP and normal transmissions. Can't find a reference for the casting #2892348, but if that is just the body number, and the part is listed as an assembly with a different number that could be the reason.

Any good source to read on the VB differences in the 66-71 time frame? What are the difference between the 66 versus 67-68, versus 69-71. Primarily interested in the V8 727. From the internal part numbers seems like the important parts are all the same. Unless the upper body had casting differences that effected performance.