trying to pull ponnies with little cash

personally if it runs I would start with the rear axle. If you don't you will break the 7 1/4 anyway!!!!! For 400 hp goal 741 8 3/4 with 373 sure grip would be plenty. 741 will take 400 all day long and cheaper than 742 or 489 I wouldn't mess with the Dana 44 the 8 3/4 is bolt and go no custom drive shaft no bs.. Personally I would dump the 318 if your going to build it anyway start with a 360 you could pick one up running for a few hundred bucks. The extra c.i. is cheap power. If you look you cold find someones old engine for cheap. Someone on here just picked up a running mopar 300hp crate for 400 bucks. Even if you bought one for 1500 its still cheap vs building one