What will me ET be with these modifications?

Maybe a couple more tenths. An intake on a stock head car wont help all that much.

Well now, if you are going with a intake it is proven that cobra matches up best with stock heads, I wouldn't get holley systemax, especially on stock heads...if you plan on going with afr's get the edelbrock rpm performer manifold it wont help you much with stock heads cause its so big but when you get the new heads in it will help alot, or if you plan on going with twisted wedge heads pick out a trick flow intake in my opinion Holley is only good for carbs

Also you can go with a new throttle body for the new manifold

24# injectors, kirban afpr, c&l 76mm leave fuel pressure at about 39psi, you will gain some hp

or of course you can do a electric fan and/or electric waterpump to free drag on motor, you can get low-mid 13's with almost stock

Don't forget the Drag radials. Tha will help you drop your ET A LOT. You can pull around 3 tenths just off the 60ft, which will be about half a second at the end of the track.

I'd concentrate more on suspension mods if your set on going fast, you have a lot of ET left in your 60', get some DR's first if you don't have em, you dont have to go nuts, just get some upper/lower control arms and your 60's should be in the 1.7-1.8 range. Thats 3-4 tenths right there...

thats a big breathing intake on a stock motor...u will gain something...but not alot