I volunteer at a military museum that has a tired M114 Armoured Personnel Carrier. These were built by Cadillac in the early 60’s and originally used a 283 SBC with the old four speed Hydramatic transmission.  We’re using a stock 350 but the original transmission is toast.  Does anyone have, or know where this is a decent Hydramatic we can use?  We have the bellhousing but we will need the coupler (converter) too.  We’re not looking for a core to rebuild – we have one already!  We’re hoping to find a usable tranny that can be run without any further work.  We’re a volunteer organization so price is important.  Thanks.