hard to say if it is a good upgrade without a lot more info on your combo 1st is this a small block or big block
Eddy Heads are not a true bolt on head , be prepared to do some work to get them on your engine , also if you have low compression now alum heads will lose close to 1 point of compression which will Not help power due to heat loss to alum , you will need to use a top quality gasket as wel such as the Cometic gasket or be prepared to change head gaskets regularly generally speaking the Eddy heads will have better flow than production iron heads
the Dak pilot brg is a roller brg not a bronze bushing , & it is pressed into an alum puck that fits int he Torque converter hub in the rear of the crank
Definatly ditch the Posi , it is a GM part