your asking a question that nobody can answer. Its not out yet so we dont have any idea what the runnners look like and how much porting will be needed or can be done.

We can answer the Trick flow question thought. The TFS heads are far superior to the stock castings. They can be ported much more and the runners can be raised higher. I have a set ported by TEA. 220cc's and they flow well over 300cfm. You wont get that out of a stock lt1 casting.

 

From the little Edelbrock has released I would say the intake will be a joke like their heads and cam are, no way of knowing that though just a guess based on the 2-7hp gains they have stated for the LT1 intake .

For a stock shortblock worked stock castings are the best bet, you will find lots of folks in the middle of a project or with a mediocre running car to argue that but a real look will show especially the 350/355 cars the fast ones VERY often have LT1 castings.
You really look to look in peoples sigs for their results when trying to get info, lot of bench racers oput there who will point you down their same missguided path to mediocre performance for way too much money.
Flow numbers and dyno charts are not speed, speed is speed.