bottom end
You seem to think "stock heads" are a lowend option even ported, well for most applications ported stock heads are the best choice.
"stock intake" again works quite well even without porting, the only readily available aftermarket alternative is from Edelbrock and proven to LOSE power.
I would say settle down and get a better handle on what this engine likes and needs before you spend any more money.
Do you have the supporting mods? Headers, stall, gears, CAI and are you prepared to have the pcm reprogrammed? If you answered no then it is not time for a cam, well obviously if the car is M6 you wont have a stall but if it is A4 you need a stall.
Trust me, I did a mild cam before I had all the supporting stuff, car drove fine but was no faster.
Here is an example of what ported stock heads and an unported intake can do on a stock shortblock.
https://ls1tech.com/forums/lt1-lt4-m...s-429rwhp.html


