Cathedral or Rectangular Port heads on 6.0
For what it's worth, I bought my complete ls3 top end including, rockers, stands, and cam for 1500 bucks. Thats brand new heads, cam and 92mm tb. Everything else was used.
Teching In
Joined: Sep 2006
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Rectangular ports on a 6.0 are what GM used to build their LY6 motors in millions of trucks so there is all sorts of knowledge about that set up. Try searching some of the truck boards for more info. Lot's of truck guys have modded those motors and have posted their dyno sheets. I know a dyno sheet isn't the only piece of information out there but at least it will give you an idea of some of the motors characteristics.
Roach
Roach
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I wouldn't run rectangle port heads on a stock bore 6.0 due to the fact it would shroud or place the big valves very close to the cylinder wall. They won't hit the wall it just isn't good for airflow. I would run big cathedral port heads unless u overbore.
If you have the money to go cathedral, go that route... However, it is extremely hard to compete with a l92 top end for the money.
I have 540$ in my heads + springs... 300$ in my intake (that flows equal to a 102) and it came with rails and the 42# injectors (saved me more money).
840$ for my complete top end assembly... I have a mild 231/236 cam in it. I'm expecting to hit 460Rwhp... You will not find any cathedral car doing that with the money you have invested, period not going to happen. Stock l92 heads sell for roughly 100$ more than a set of 243 heads and FAR outperform them. Could you go out and spend money on a FAST and a nice set of ported heads? Sure, and it would have better mid range to boot... But I didn't have money for a 370+that.. My setup will perform perfect for what I'm running and run me into the 6s easily. I'm not going to spend 2,000$ extra for better "feeling" below 3500RPMs and a couple Rwhp here and there on the sheet, not worth it in my eyes.. Thats only 900$ cheaper then I spent for my entire 370 assembled and shipped to my door.
I can still port my heads/intake and then I'm looking closer to 490Rwhp, not bad through a large stalled auto, 6 speed would be over 500Rwhp with ease.
L92 heads are an awesome head choice... If you don't want to spend a couple thousand dollars more for somewhat similar gains, it is a given.
I have 540$ in my heads + springs... 300$ in my intake (that flows equal to a 102) and it came with rails and the 42# injectors (saved me more money).
840$ for my complete top end assembly... I have a mild 231/236 cam in it. I'm expecting to hit 460Rwhp... You will not find any cathedral car doing that with the money you have invested, period not going to happen. Stock l92 heads sell for roughly 100$ more than a set of 243 heads and FAR outperform them. Could you go out and spend money on a FAST and a nice set of ported heads? Sure, and it would have better mid range to boot... But I didn't have money for a 370+that.. My setup will perform perfect for what I'm running and run me into the 6s easily. I'm not going to spend 2,000$ extra for better "feeling" below 3500RPMs and a couple Rwhp here and there on the sheet, not worth it in my eyes.. Thats only 900$ cheaper then I spent for my entire 370 assembled and shipped to my door.
I can still port my heads/intake and then I'm looking closer to 490Rwhp, not bad through a large stalled auto, 6 speed would be over 500Rwhp with ease.
L92 heads are an awesome head choice... If you don't want to spend a couple thousand dollars more for somewhat similar gains, it is a given.
TECH Fanatic
Joined: Aug 2011
Posts: 1,324
Likes: 6
From: Marengo, Ia
Because fully ported 243's have a hard time making that kind of power with a 22x cam, and even then they wont make as much torque. Take a look at that torque curve again thats the impressive part of that motor not the peak numbers.
It's making 400lbs. of tq by 3200rpm and 425lbs. by 3600rpm, and 450hp by 5300rpm. Your not going to do that with lightly worked 241's.
It's making 400lbs. of tq by 3200rpm and 425lbs. by 3600rpm, and 450hp by 5300rpm. Your not going to do that with lightly worked 241's.
TECH Fanatic
Joined: Aug 2011
Posts: 1,324
Likes: 6
From: Marengo, Ia
Because I know the price it would take to make those numbers.. I didn't just jump into an l92 setup blind... I did my research, I know prices, I know the results.
You aren't going to make the same power with a cathedral port for the money, just different worlds.
Show me a set of 500$ (stock 243s) set of cathedral heads with a 175$ intake (ls2 intake) making anywhere close to that power. We both know it isn't possible to make that kind of power with stock 243s/stock ls2 intake in a 6.0 or even a 6.2.
Hell even saved money on the injectors since it came with 42# but we won't factor that in cause it would be unfair.
The L92 heads/intake flow stupid numbers out of the box... They might not be the best choice for every setup but the definitely have a place, especially once money is brought into the equation.
You aren't going to make the same power with a cathedral port for the money, just different worlds.
Show me a set of 500$ (stock 243s) set of cathedral heads with a 175$ intake (ls2 intake) making anywhere close to that power. We both know it isn't possible to make that kind of power with stock 243s/stock ls2 intake in a 6.0 or even a 6.2.
Hell even saved money on the injectors since it came with 42# but we won't factor that in cause it would be unfair.
The L92 heads/intake flow stupid numbers out of the box... They might not be the best choice for every setup but the definitely have a place, especially once money is brought into the equation.
Because I know the price it would take to make those numbers.. I didn't just jump into an l92 setup blind... I did my research, I know prices, I know the results.
You aren't going to make the same power with a cathedral port for the money, just different worlds.
Show me a set of 500$ (stock 243s) set of cathedral heads with a 175$ intake (ls2 intake) making anywhere close to that power. We both know it isn't possible to make that kind of power with stock 243s/stock ls2 intake in a 6.0 or even a 6.2.
Hell even saved money on the injectors since it came with 42# but we won't factor that in cause it would be unfair.
The L92 heads/intake flow stupid numbers out of the box... They might not be the best choice for every setup but the definitely have a place, especially once money is brought into the equation.
You aren't going to make the same power with a cathedral port for the money, just different worlds.
Show me a set of 500$ (stock 243s) set of cathedral heads with a 175$ intake (ls2 intake) making anywhere close to that power. We both know it isn't possible to make that kind of power with stock 243s/stock ls2 intake in a 6.0 or even a 6.2.
Hell even saved money on the injectors since it came with 42# but we won't factor that in cause it would be unfair.
The L92 heads/intake flow stupid numbers out of the box... They might not be the best choice for every setup but the definitely have a place, especially once money is brought into the equation.
What are you on?
Go find me ONE 6.0 or 6.2 liter with the equivalent to STOCK 243 heads with a STOCK ls2 or even ls6 intake that makes 480+Rwhp with a mid size cam. 6.0/6.2 with STOCK l92 top ends make 480+Rwhp all day long with mid size cams (some would consider them on the small side even).
I will be waiting, and won't hold my breath.
Are you not reading everything being posted or just not understanding it?
Go find me ONE 6.0 or 6.2 liter with the equivalent to STOCK 243 heads with a STOCK ls2 or even ls6 intake that makes 480+Rwhp with a mid size cam. 6.0/6.2 with STOCK l92 top ends make 480+Rwhp all day long with mid size cams (some would consider them on the small side even).
I will be waiting, and won't hold my breath.
Are you not reading everything being posted or just not understanding it?
TECH Fanatic
Joined: Aug 2011
Posts: 1,324
Likes: 6
From: Marengo, Ia