Do I need bigger primaries???
#1
Do I need bigger primaries???
I am currently having a 457 lsx built for my 03 silverado ss. I currently have pacesetter LT with 1 3/4" primaries and 3 inch collectors. At this time 1 3/4" primaries are the biggest available for my truck. I am wondering if custom headers with maybe a 1 7/8" primary or even a 2" primary would be benifitial to me. I am thinking they would, but I am also thinking that maybe the 1 3/4" primaries will give me more back pressure creating more torque to get my 5,300lb beast moving. I just want to make my truck as fast as possible. Any help would be appreciated. Here are the specs on the motor:
LSX block
-LS7 heads (stock intake side, but the exhaust has been reworked by WCCH)
-Ported LS7 manifold (jeremy Formato)
-4.200" bore
-4.125" stroke
-6.125" rods
-Custom CP pistons with a reverse dome of the ls7 combustion chamber
-SCR of roughly 11.2:1
LSX block
-LS7 heads (stock intake side, but the exhaust has been reworked by WCCH)
-Ported LS7 manifold (jeremy Formato)
-4.200" bore
-4.125" stroke
-6.125" rods
-Custom CP pistons with a reverse dome of the ls7 combustion chamber
-SCR of roughly 11.2:1
#2
Originally Posted by adams2003
I am currently having a 457 lsx built for my 03 silverado ss. I currently have pacesetter LT with 1 3/4" primaries and 3 inch collectors. At this time 1 3/4" primaries are the biggest available for my truck. I am wondering if custom headers with maybe a 1 7/8" primary or even a 2" primary would be benifitial to me. I am thinking they would, but I am also thinking that maybe the 1 3/4" primaries will give me more back pressure creating more torque to get my 5,300lb beast moving. I just want to make my truck as fast as possible. Any help would be appreciated. Here are the specs on the motor:
LSX block
-LS7 heads (stock intake side, but the exhaust has been reworked by WCCH)
-Ported LS7 manifold (jeremy Formato)
-4.200" bore
-4.125" stroke
-6.125" rods
-Custom CP pistons with a reverse dome of the ls7 combustion chamber
-SCR of roughly 11.2:1
LSX block
-LS7 heads (stock intake side, but the exhaust has been reworked by WCCH)
-Ported LS7 manifold (jeremy Formato)
-4.200" bore
-4.125" stroke
-6.125" rods
-Custom CP pistons with a reverse dome of the ls7 combustion chamber
-SCR of roughly 11.2:1
Back on topic, the backpressure is great down low but over 3000 RPMS it will be a limiting factor. look for a custom header but that is some big bucks
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#9
Originally Posted by seeyaa
is that 457 going in a 4x4 also where you from because i want a ride when that things fireing
Its going into a AWD silverado ss. Fly out to california and you can have a ride.
#10
8 Second Truck Club
iTrader: (32)
You said "as fast as possible".
I would either get a stepped 1-7/8 to 2 or just a straight 2".
I used to run a 461 inch big block in a truck with 2" headers and they worked great. With that many inches torque is not an issue.
I assume money is not a problem with this build.
I would either get a stepped 1-7/8 to 2 or just a straight 2".
I used to run a 461 inch big block in a truck with 2" headers and they worked great. With that many inches torque is not an issue.
I assume money is not a problem with this build.