do i have a TH400 transmission in my '84? need your help!

[yellow400ex05]

I have a 427 swapped '84 C10 and wanted to know what transmission i have so i can order a stall converter for it.

i read that you can tell my the shape of the oil pan, well here's a picture of the best i could take (truck is lowered)

here's the tag first if this helps


trans oil pan, yes is greasy sorry haha but it gives you the shape of the pan. taken from the passenger side of the truck