69 Notch Barracuda - Rebirth

Trans breakdown (no info on previous operation of trans)... no broken needle bearings, no metal in the case, all seemed tight. Seemed to be normal wear on the leading edges of teeth. Besides a basic rebuild kit... Not exactly sure what I'm looking for as far as replacement of parts. If anybody has any advice on specifics it would be much appreciated. Otherwise I'll be doing more research and reaching out to the experts, etc...