Cathedral vs ls3 test on a 408
10-21-2017, 12:44 PM
#23
11 Second Club
10-21-2017, 12:47 PM
#26
It's called Minimum Cross Sectional Area. If you don't have enough, or if you have too much, you won't make much power. MCSA is limited by your valve size. The 317 casting has 2" intake valves but the 821 and AFR heads have 2.165" intake valves.
So it's a lot like trying to breathe through a coffee stirrer versus a paper towel roll. The rectangle port makes good power just because it has more adequate MCSA. To get the same MCSA out of a cathedral head, you need to do a lot of work to an OEM casting or start with an aftermarket casting.
I'm sure you understand this, but carry on with your troll posts.
So it's a lot like trying to breathe through a coffee stirrer versus a paper towel roll. The rectangle port makes good power just because it has more adequate MCSA. To get the same MCSA out of a cathedral head, you need to do a lot of work to an OEM casting or start with an aftermarket casting.
I'm sure you understand this, but carry on with your troll posts.
10-21-2017, 12:57 PM
#27
11 Second Club
with ya.....
10-21-2017, 01:07 PM
#30
11 Second Club
10-21-2017, 03:07 PM
#31
It's called Minimum Cross Sectional Area. If you don't have enough, or if you have too much, you won't make much power. MCSA is limited by your valve size. The 317 casting has 2" intake valves but the 821 and AFR heads have 2.165" intake valves.
So it's a lot like trying to breathe through a coffee stirrer versus a paper towel roll. The rectangle port makes good power just because it has more adequate MCSA. To get the same MCSA out of a cathedral head, you need to do a lot of work to an OEM casting or start with an aftermarket casting.
I'm sure you understand this, but carry on with your troll posts.
So it's a lot like trying to breathe through a coffee stirrer versus a paper towel roll. The rectangle port makes good power just because it has more adequate MCSA. To get the same MCSA out of a cathedral head, you need to do a lot of work to an OEM casting or start with an aftermarket casting.
I'm sure you understand this, but carry on with your troll posts.
10-21-2017, 04:29 PM
#35
LS7 heads are superior to and make more power than cathedrals and ls3's...
If you're going to bother bolting on new heads and intake.. ls7 it
If you're going to bother bolting on new heads and intake.. ls7 it
10-21-2017, 04:41 PM
#36
TECH Veteran
Too bad LS7 heads are known for dropping valves and destroying motors. Plus you just can't slap a pair of LS7 heads on a 4 inch bore motor.
10-21-2017, 05:01 PM
#37
Aftermarket small bore LS7 heads aren't dropping valves.
10-21-2017, 05:10 PM
#39
TECH Veteran
I just got one question. What do a 40X cube car with stock LS3 heads/cnc/aftermarket, hydraulic roller, fast type intake, pump gas car usually run in the quarter in a 1/4 mile?