Most cai are 3.5 and even 4" draws vacuum

I've don't numerous tests on track and dynos to prove it

This is also why you see better numbers from some vs others

The dual 4" was worth 5 rwhp over single and kept kpa up entire pull

 

ls1, 5.3 heads ported,ms4 cam, fast 90/90, 4000 stall, and 4.30 gears got me 11.9 with a 1.8 60 ft on drag radials. i drove the truck every day with this motor

 

I do already have a 4" intake and am def willing to try different intake combos. Seems that with 4.56 gears it would be like me cruising in 3rd so im going for a cruise when I get off to see how barable it is.
Monte, any reason you went with the 862 heads over a 243?

 

i build this motor in 05 and the 243 were to hard to get and expensive, so it was a budget build