omarsr67

Just asking because measuring the ports, rectangle v cathedral, they are the same width and height. The difference being the cathedral Port obviously taper in at the top giving it the cathedral window shape. There is a video on YouTube of someone bolting up an LS3 intake onto cathedral port engine with no modifications. He put new intake gaskets on the LS3 intake and that's it. It sealed up with no vacuum leaks. Why do people say it won't work without adapters? If you look at the adapters, one side tapers in at the top the other side doesn't. Other than that they're the same dimensions.

RB04Av

"Work" = sure, why not

"Best" "right" "optimum" = ???

Not sure where you're going with this.

TrendSetter

Same width and height? Really?

Rich-L79

In the big block Chevy world it is not uncommon to bolt a rectangular port manifold onto large oval port heads. It works surprisingly well.

BFK86

iTrader: (1)

Only way to know is to test it on a dyno, always heard the adapters hurt power, so I can imagine with no adapter smoothing out the airflow going in to the head it probably won't work too well. The better test would be a NNBS rectangle port vs a TBSS cathedral port bolted up to the same cathedral port heads, basically the same intake design between both outside of the port shape. That would tell you whether the difference in port shape would hurt flow.