How to sync to speed duration

[Ezad]

Hello
The tiny film clip is a sample of the difficulties I am encountering attempting to sync audio to video. I can sync at the start and at the end and while playing the clip(s) the sync moves in and out. I don't know what to do unless the solution is with the speed and duration.
Is the solution with syncing to speed?
If so how is this done to make the vocal play as it should?
Thanks for any insight. 

https://youtu.be/_qg6UZ3WmNw

[Phillip Harvey]

How are these media files being acquired? You're getting separate video and audio? What are the specs? Does the video have Variable Framerate?  https://www.reddit.com/r/VideoEditing/wiki/faq/vfr

[Ezad]

This work is with a non profit organization. 

A member recorded on a Super 8 camera multiple interviews from 1971-1975.
The audio was recorded separately on a cassette recorder.
Our non profit did a fund raiser to have the reels transfered at a Transfer House.

The reels were transfered from 8mm and super 8 to HD 2K Pro Res .MOV - and the audio cassette tape to .WAV

The audio files have no 'markers' thus it is all manual to sync - and I wonder if there is a need to adjust the speed of the audio.

Thanks for commenting!
The link to the article will take time to digest.....

[Ezad]

The properities of the MOV asset is:

FrameRate  24:00 frames/ second

[Ezad]

[Phillip Harvey · Accepted solution]

Thanks for posting with the details. My thoughts are exactly in line with what Peru Bob and Richard M Knight have said. Issues with the consistency of the recordings when they were captured. There's not automated way to deal with that kind of drift that I'm aware of. I'd approach it manually as Richard suggested. A dedicated audio software might give you a little more of a toolset to deal with something like that - being able to more dynamically speed up and slow down the audio. Premiere has Time Remapping for video but not for audio (although you could arguably approach it by remapping the video but that'd be up to you.)

[Peru Bob]

and the audio cassette tape to .WAV

By @Ezad

The cassette tape may have had inconsistencies in the speed.

You might just have to spend some time manually cutting and syncing.

[Richard M Knight]

Cassette recorders were never speed accurate, drifting a second a minute was not uncommon. I can think of no easy way to sync the audio. Try syncing the start and use  the rate stretch tool (shortcut R) to pull the end into sync. You may have to cut the audio and do it in small sections.