Greg, you guys have it correct. FYI you can get oem heads from endyn from the pr3 cast non ITR.
I can touch on a couple of things.
The butterflies in the manifold were also on the h22 prelude vtec motor and is used for more torque in city/lower rpm driving and also supposed to improve fuel efficiency until vtakkkk.
The gsr head is not as bad as people make it out to be, the combustion chambers have been quenched so if you swapped a b16 head on your gsr you would have a decrease in compression stock for stock. The b16 head flows about 5 cfm better than the gsr so its not terribly different. The intake manifold stock for stock is the issue between the 2 in my opinion (b16a3 is the best under ITR).
FWIW
The one thing people don't realize is the intake side of the gsr head was designed to accept the inverted manifolds design. The runners need to be properly angled where they meet the head, AEBS actually was proven to make more power over the skunk/ITR style manifolds. I used this on my built gsr motor I had with a lot of success.
I can touch on a couple of things.
The butterflies in the manifold were also on the h22 prelude vtec motor and is used for more torque in city/lower rpm driving and also supposed to improve fuel efficiency until vtakkkk.
The gsr head is not as bad as people make it out to be, the combustion chambers have been quenched so if you swapped a b16 head on your gsr you would have a decrease in compression stock for stock. The b16 head flows about 5 cfm better than the gsr so its not terribly different. The intake manifold stock for stock is the issue between the 2 in my opinion (b16a3 is the best under ITR).
FWIW
The one thing people don't realize is the intake side of the gsr head was designed to accept the inverted manifolds design. The runners need to be properly angled where they meet the head, AEBS actually was proven to make more power over the skunk/ITR style manifolds. I used this on my built gsr motor I had with a lot of success.