Building custom intake plumbing......

[John McIntire]

I was thinking about building some custom plumbing, to feed my throttle body.
I was thinking of two 3 inch pipes, they tuck down by the radiator near the bottom with cone filters, and then work there way up and merge into the throttle body.
Is 3 inch large enough? should I use 4 inch?? It's GM's 572/620HP version, so I was worried about airflow a little. I dont want to starve the engine for air.
Thanks in advance!!!!
John

[WS6]

two 3" pipes merging into a 4" pipe should do you well. what size is the the TB opening? i would use that as the final size and not just neck it down right before the TB. that's if it happens to be smaller than 4"