Currently I have a ls1 w/cam in my car, swapping to a 408 with heads cam intake will the stock tpi air box be restrictive should I make a cold air intake? I like the stock look and fit but if restrictive it’s gone. Thanks for any input

 

Waaaaay restrictive. But you can give it a try and look at your MAP sensor values at wide open throttle.

A 4 inch intake and very large filter was on the hairy edge for my 427 stroker. I had to bump up to a 5 inch intake with the LS7.

 

This is a 408 LS2 with CNC’d LS3 heads and an aggressive cam. The CAI is 4”, which is the minimum for this motor as QuickTrip stated. You’re not going to want to chock that motor. I’m also running a dual 3” exhaust on my motor.

 

Thanks for the help ..I think I’m gonna fab me a 4” cold air intake for sure

 

what MAF did you use ..the LS3 style?

 

If you built a ram air box to forcefeed the tpi y lid, it would work decent. The Y only flows around mid 700’s cfm. You can custom make one a bit taller like Chad Speier is doing for his 530 hp 379. But its alot of work

a good air intake is better idea tho

 

Yes, it is the blade style. I don't remember where I got the aluminum adapter for the aluminum tube, but shouldn't be that hard to find one. I believe the wiring conversion is on this forum somewhere.

 

When yer engine is moving enuf air to feed those ci, you need 4"-5" AND high pressure area of the car, higher rpm=bigger inlet

 

I say Chad's efforts were well worth it.

https://www.thirdgen.org/forums/fabrication/768690-my-cold-air-intake.html

That he could bench flow his creation lends some credibility to the project. What I found really interesting is his statement that the air filters represented zero restriction. This contrary to what I've read from tech articles and K&N but who am I to argue with a flow bench.