1959 Other Chevrolet Models rear differential

1959 Other Chevrolet Models V8 Two Wheel Drive Automatic

I have a 1940 chevy coupe. I bought a rearend from a friend and installed it. I now have leaks on all the seals and would like to replace them but the problem is I have no idea what one this is. It's a G.M. Thinking a 1955 chevy 1/2 ton. The differential comes out from the front not the rear it doesnt have a rear cover. It has 10 bolts. Also would this rearend hold up to 400 H.P.