Who has LS7 cam dyno graphs with cathedral port heads?
04-09-2018, 08:28 AM
#21
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You must read alot more internet lists than you build hammer. I know Judson, had lunch on him a couple times actually LOL, but that is the most wrung out NA LS car on the planet - worlds removed from what 99% of these things are doing its twin TB 10,400 rpm engine.
The heads needs to be APPROPRIATELY sized for the task at hand. Most arent tasked with going 4.30s in the 1/8 or 10k. The port shape has little to do with anything. If the shape alone was the answer, the square port LS3 would have been on the C6 Z but it sucked so they had to revise it.
You drew a picture of what you THOUGHT a cathedral headed 427 might do on Microsoft paint, Ive done it LOL
Ive seen that cam test artical, but its on a 5.3, and a long runner truck intake which is a little further away from design. I said eff it though and the LS9 cas are going in 8 degrees advanced, well 7 because the timing set is a little off
The heads needs to be APPROPRIATELY sized for the task at hand. Most arent tasked with going 4.30s in the 1/8 or 10k. The port shape has little to do with anything. If the shape alone was the answer, the square port LS3 would have been on the C6 Z but it sucked so they had to revise it.
You drew a picture of what you THOUGHT a cathedral headed 427 might do on Microsoft paint, Ive done it LOL
Ive seen that cam test artical, but its on a 5.3, and a long runner truck intake which is a little further away from design. I said eff it though and the LS9 cas are going in 8 degrees advanced, well 7 because the timing set is a little off
The ls3 ports were designed after the Ls7\c5r heads were they not?
A cathedral headed 427 would actually be great in a truck
04-09-2018, 12:10 PM
#22
No the LS3 ports were designed for the Z06 C6. When the motor didnt meet power goals (it was originally 396" I believe? this is from conversation with the guy that ran the design team 10+ years ago so hard to remember) they decided to fix the heads AND make it bigger. They chased alot of issues with ring seal and odd chatter from the honing machines at first as well. The heads have the same 260cc port size... but they moved the valve locations which gave some room for more valve area, rolled it over to 12 degree and raised the port to help with that **** short turn, put a better geometry rocker setup on it etc etc and it was a pretty bad *** pushrod motor
The best head I think Ive ever used for a typical NA engine was a 235cc port, 2.08/1.60 valve. But it WAS a LS7 location port so you could use an stock LS7 intake (best manifold at the time that wasnt a tunnel ram). That thing ran its *** off for my first attempt at building an NA setup
04-09-2018, 12:24 PM
#23
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I am struggling with how a 235cc runner is optimal for a 427. Unless the runner is very short and the port area is large
04-09-2018, 01:08 PM
#24
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04-09-2018, 01:32 PM
#26
Pretty sure engines dont know what you call them
Or what you call their heads.
It struggled to a 9.50 at 143 on the motor with a untouched factory intake manifold, .6xx" hydraulic roller, yella terra rockers arms, 11:1 compression, basic bitch. Had a 1.25 60 ft once, but never put both ends together. Should have went .30s This was 10+ years ago
Or what you call their heads.
It struggled to a 9.50 at 143 on the motor with a untouched factory intake manifold, .6xx" hydraulic roller, yella terra rockers arms, 11:1 compression, basic bitch. Had a 1.25 60 ft once, but never put both ends together. Should have went .30s This was 10+ years ago
04-09-2018, 01:58 PM
#27
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Pretty sure engines dont know what you call them
Or what you call their heads.
It struggled to a 9.50 at 143 on the motor with a untouched factory intake manifold, .6xx" hydraulic roller, yella terra rockers arms, 11:1 compression, basic bitch. Had a 1.25 60 ft once, but never put both ends together. Should have went .30s This was 10+ years ago
Or what you call their heads.
It struggled to a 9.50 at 143 on the motor with a untouched factory intake manifold, .6xx" hydraulic roller, yella terra rockers arms, 11:1 compression, basic bitch. Had a 1.25 60 ft once, but never put both ends together. Should have went .30s This was 10+ years ago
04-09-2018, 03:49 PM
#29
TECH Senior Member
04-09-2018, 03:54 PM
#31
TECH Senior Member
04-09-2018, 04:08 PM
#32
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Torque port wars!!!!! Episode 31: here we have the team of square porters spitting out knowledge from their own impressive results vrs an old school 235cc cathedral tuner whos built many LSx in his day. Results have been posted off youtube...... How about some own personal achievements with dyno numbers funded by each individual and your current motor specs. Im betting 2 of them have square ports and the cathedral has a turbo hanging off it lol Ive seen the volvo lol Hope all is well Granny! Phil
04-09-2018, 05:20 PM
#33
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Originally Posted by spanks13
There is nothing magical about the intake port being shaped like a urinal.
This argument is so dumb.
I guarantee a Stock LS7 head will make more power on a 427 than a 235cc urinal port.
This argument is so dumb.
I guarantee a Stock LS7 head will make more power on a 427 than a 235cc urinal port.
04-09-2018, 05:25 PM
#34
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Originally Posted by G Atsma
I guess I wasn't clear either! lol
I meant the length of the port from manifold surface to the valve. A shorter, larger cross-section port can equal the volume of a longer, smaller cross-section port.
I meant the length of the port from manifold surface to the valve. A shorter, larger cross-section port can equal the volume of a longer, smaller cross-section port.
And shape means very little. CSA is what matters along with runner dynamics like how tight that short turn is, etc
04-09-2018, 11:58 PM
#36
Torque port wars!!!!! Episode 31: here we have the team of square porters spitting out knowledge from their own impressive results vrs an old school 235cc cathedral tuner whos built many LSx in his day. Results have been posted off youtube...... How about some own personal achievements with dyno numbers funded by each individual and your current motor specs. Im betting 2 of them have square ports and the cathedral has a turbo hanging off it lol Ive seen the volvo lol Hope all is well Granny! Phil
At least Ive actually done what Im talking about
The following 2 users liked this post by GrannySShifting:
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04-10-2018, 12:10 AM
#37
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DualQuadDave (09-19-2023)
04-10-2018, 07:27 AM
#39
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04-10-2018, 10:48 AM
#40
Dyno numbers are about meaningless to me except as a comparator A-B testing on that unit. Ive seen alot of "750 hp" dyno sheets than could barely go 134 in the 1/4 while we would go 143 with 530 hp on my dyno. Outside on planet earth has always seemed to be a better measuring stick than make believe dyno graphs. I went 132 with 470hp heads/cam 6.0 at 3600# Let me know what it runs when you get it to track, should haul the mail
Looks like it rpms well, prob pretty fun car to drive, good choice getting rid of some of that runner length (but not all of it)