Replacement engine

[53burb]

Once I get my starter situation straightened out, I am going to start considering an engine replacement. I have decided to either go with this stock replacement engine engine and upgrade it with an Edelbrock cam, lifters, and intake manifold set. Or this one,engine and just add an intake manifold. I want it to be in the 300-350HP range. It will have dual exhaust w/rams horn manifols and I will be using an Edelbrock 1806 650cfm carb and HEI iginition. What value does Vortec heads have? Both engines are 4-bolt mains. The stock one uses a 2-piece rear seal and the 330-HP uses a 1-piece seal. Also, is it recommended to use a HV oil pump?? The tranny is another story.