This gets expensive because you still have to purchase a set of Vortec heads, so we'll concentrate on retaining the stock heads for budget reasons. The intake is PN 12496821 ($370 from Scoggin-Dickey).
There are ways around that by using a GM Performance Parts aluminum intake that bolts to the Vortec heads and features a stock mount for the TBI. However, the Vortec heads use a different intake bolt pattern that does not match up to the TBI intake manifold. These heads flow very well and would be a good choice to make 300 hp with a mild camshaft. The best approach would be to go with a stock camshaft and a set of Vortec iron heads. Before we get to the electronic side of things, it sounds like you have a new engine ready to go into the truck.