Cathedral or square port heads?

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Oct 27, 2014 | 05:16 AM

#21

Tuskyz28

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From: Mississippi

Quote:

Originally Posted by American Psycho

The rectangular port LS3 heads can flow over 300cfm straight from the factory. The cathedral port cant come close to that.

I thought I did read somewhere that the cathedral port heads were better at generating air velocity at a lower RPM, can anyone validate that?

Good question.... The LS3 head is a great head. Best bang for the buck for a motor with a 4.000 bore or bigger. The LS3 head is pretty much like the double humps/vortec heads of the sb chevy imo. On the intake side the LS3 head is killer but the exhaust sucks... mainly that's why I think the CAM SELECTION makes them or breaks them. Overall the LS3 head have a poor intake/exhaust relationship. It's kinda hard to compare a set of 1000 dollar head to a head that costs 2500 per set. Now if you look at cathedral port heads intake/exhaust relationship you'll notice it's a lot better. I honestly think that have a lot to do with the total package of the setup. We all know as gear heads the more air you get in (intake) the more air you need to get out (exhaust). Which goes a lot with the "velocity" deal. My conclusion... The LS3 head is a great head but not the ultimate head.

Oct 27, 2014 | 01:42 PM

#22

Jacktuner

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From: Newcastle

http://www.cpgnation.com/car-craft-ls-cathedral-port-vs-square-port-heads

Interesting article this cathedral head makes more torque below 4000rpm but its not far in front of the square port

Oct 27, 2014 | 11:24 PM

#23

CattleAc

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From: Dakota Territory

Quote:

Originally Posted by Jacktuner

http://www.cpgnation.com/car-craft-ls-cathedral-port-vs-square-port-heads

Interesting article this cathedral head makes more torque below 4000rpm but its not far in front of the square port

Very interesting...

Here's a "clickable" link...

http://www.cpgnation.com/car-craft-l...re-port-heads/

Oct 28, 2014 | 12:51 AM

#24

Tuskyz28

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From: Mississippi

Quote:

Originally Posted by CattleAc

Very interesting...

Here's a "clickable" link...

http://www.cpgnation.com/car-craft-l...re-port-heads/

Good article!! Let's compare some more engines tho. Rectangle vs cathedral

Lme 427ci
TFS 255 cc 12 degree LS3 head
12:1 compression
fast 102 mm intake / tb
248/264 cam
644 hp/580tq

Vs

Tony Mamo 434 ci
Afr 245 cc cathedral port head
11:6 compression
247/251 cam
Fast 102 mm intake/ tb
678 hp/600 ftlb

I know mamo motor has more cubes but not by far (only 7ci difference) but LME motor has more compression.... I have a link to both builds if you guys want to see them for yourself. If you look at lme 427 motor the torque curve does like a hill. It starts low goes up and then slowly back down. Look at mamo 434 motor the torque curve look flat at a pool table and it produces more horsrpower on less compression.

Nov 21, 2014 | 02:57 AM

#25

Jacktuner

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From: Newcastle

Well after much thought ive gone with stock ls3 heads on my litre with a 218/225 113 cam, 600/575 lift, drove another 6 litre with the same combination and it went awsome, good power and still drivable