Correct , just wanting to know if a 71 vb. will work with the 78 case that had the lockup vb .
If you want to disable lockup just block the lockup valve. No need to switch valves bodies. On the 78 there is a lockup module with an aluminum tube running to it. Just block the valve by replacing the spring inside with a plug.
IIRC yes the 71vb will fit the 78 727 as you have converted the spline/TC to non lock up.
IIRC the 71 VB will NOT have a PTK valve. you can use a housing/spring/valve from a /6 904 trans on the 71 VB for a PTK. (IIRC this is what I did for my 67-727 for PTK)
IIRC the 78 VB would have PTK with a downshift limiter built into it.
904 and 727 lock up trans I have had, I blocked the valve and order up a fresh lock-up TC with out the clutch ring/guts in the TC and use the non-lock up spline/shafts to save on teardown and parts.
but then again I have broke and killed more than I have ever been able to fix so hopefully someone will confirm for sure 100% + for you.
I have a good 78-727 VB on the parts shelf if you would prefer to use a 78 VB in the 78 case. PM me if you are interested.
Maybe I didn't explain it enough , l do not want a lockup 727 , I have non lockup stahl converter I want to use , changed the components for non lockup , and have a 1971 vb I wanted to use and was not sure if it would work in the 1978 case . I want to save the lockup vb for another time and the other parts . I thank you for the reply .
If you have replaced the front pump assembly, input shaft and rear clutch piston retainer to pre-'78 non-lockup parts (or '78-later non-lockup parts), then, yes you can use the '71 VB. The factory has stated that the lock-up case can be used for "prior model service".