IAMC4CRAZY

Help,

I am putting together a project vehicle that i have the opportunity to buy a brand new lm7 long block for 1200.00 and the heads have the cathedral ports. The issue here is I have a 2001 ls1 corvette Intake Manifold that i want to use with rectangular ports. Will they mate together, do I have to change heads, is there a special adapter that I can buy????? Any input will help!!

NVR_SPDS

iTrader: (39)

The LS1s are a cathedral port head, so youll be just fine. No adapters or anything else needed.

IAMC4CRAZY

How will the rectangular ports match up to the cathedral ports on the heads? Won't there be an air gap near the top of the heads?

pairof69s

you can't put cathedral port intake on square port head, or vise versa

IAMC4CRAZY

Now i am definately confused! From what i have read all ls1 motors, including in Corvettes up to 2001 had cathedral port heads, but the intakes all have the Rectangular ports. "NVR SPDS" says they will match up and now "pairof69s" says they won't! I value all you guys inputs, but i need definate clarification here!

NVR_SPDS

iTrader: (39)

The LS1/2/6, LM7, LQ4/9 (i know im forgetting some others) are all cathedral port heads, the intake itself is NOT cathedral in shape, it actually is rectangular in shape, so all these bolt up to the cathedral ports. Just as the LS1 came with the LS6 manifold.

The LS3/L99 head ports are rectangular, but they are a shorter, wider port design. The LS7 IIRC is also a rectangular port, but with a design, and port spacing all its own.

Ill see if i can dig up the thread showing the differences.

IAMC4CRAZY

Thanks fellow ls'ers! I really appreciate the imput! Hey "NVR SPDS", I am assuming that you have now clarified that these are a match, but i am still looking forward to that thread you spoke of!

NVR_SPDS

iTrader: (39)

No problem at all. There was a thread showing all the port designs, and I believe it showed how the intake ports matched up to the individual heads, so if someone has the link, please post it. Ive been searching for it, with no luck yet.

StryfeS13

iTrader: (2)

Good info to know. I'm doing an LM7 as well and needed to know if I could use an LS1 intake

cbenn47

iTrader: (2)

So not to butt in, but I just purchased a LS-6 intake for my 5.3 I'm building, when I received it the intake has what looks like rectangle ports and my 5.3 heads have the cathederal ports, can I use this intake, do the LS-6 intake come with either rectangle or cathederal ports? very confused at this point if I can use this intake or not.
All replies are appreciated.

JakeFusion

iTrader: (7)

Everything prior to the LS3 used a cathedral port head design, whether Gen III or Gen IV, truck or car.

Gen IV LS3/L76 changed to the rectangle port design. LS7 is a raised rectangle port.

And when we talk about port design, we mean the heads.

The manifolds are all rectangle in shape, but will not mate up to another head port design... i.e., LS1 and LS3 are not interchangeable.

So as long as the intake you bought is LS1,2,6 or the LQ9/4 or LM7, L33 truck intakes, they will all work on any cathedral port head.

redtan

iTrader: (5)

The may look rectangular, but they are made for cathedral port heads. They just don't have the same shape as the top of the head port, but they are long and skinny.

The real "rectangular" ports that you hear of from the LS3s are completely different.

cej2525