transmission adapter plates

I have a 83 gmc 2500, I am wanting to put a olds 350R in the truck but I know I have to use an adapter plate to match up the tranny.. my question is, if anyone can help.. the only adapter plates I have found do not specify if they are for automatic trans or universal.. I have written the manufactorers but no response as of yet.. does any one know? My truck has a 4 speed truck tranny standard.. thanks for any input..

I did some research and searching, I was told the best thing to do was to get a BOP bell-housing for a standard tranny. Do some modification for the motor mounts and I should be on the right track. Does anyone know if there are any after market BOP bell housings available? Do I need to post this on a different area on the forum? Well, have a safe and good day. Texas Rivers