LQ4 head and cam questions
Thread Starter
Teching In
Joined: Feb 2011
Posts: 9
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LQ4 head and cam questions I recently purchased an LQ4 engine from a 2500 Silverado. I am also new to the LS world and this site. The engine will be used primarily for street use with the occasional track time. I don't think the L92 heads would be a good option, because I'm not interested in most of my power at the top end and lower C/R. I want to maximize torque at lower RPM. I'm looking for any input or suggestions.
The engine will be NA and I was thinking of using a 224R or 228R cam. Also, I'm thinking of using 243 heads to increase the C/R. I'm looking to get the C/R around 10.5:1 or close. What would the C/R be on unmilled 243's on an LQ4 with stock head gaskets? I'm figuring about 10.2:1. Would I also need to flycut the pistons or would they be ok?
Would the PRC Stage 2.5 LS6 heads or even the stage 1 heads be an option for what I'm looking for? I'm not saying money is no option, but if I can save to do it right the first time, I will be happier in the end.
Also, any idea what flywheel numbers might be?
The engine will be NA and I was thinking of using a 224R or 228R cam. Also, I'm thinking of using 243 heads to increase the C/R. I'm looking to get the C/R around 10.5:1 or close. What would the C/R be on unmilled 243's on an LQ4 with stock head gaskets? I'm figuring about 10.2:1. Would I also need to flycut the pistons or would they be ok?
Would the PRC Stage 2.5 LS6 heads or even the stage 1 heads be an option for what I'm looking for? I'm not saying money is no option, but if I can save to do it right the first time, I will be happier in the end.
Also, any idea what flywheel numbers might be?
l92's that have been milled some will be just fine down low as long as you dont put too large of a cam in it.
I suggest you try doing some more reading and searching its going to be real hard to get all those questions answered in one post.
I suggest you try doing some more reading and searching its going to be real hard to get all those questions answered in one post.
I recently purchased an LQ4 engine from a 2500 Silverado. I am also new to the LS world and this site. The engine will be used primarily for street use with the occasional track time. I don't think the L92 heads would be a good option, because I'm not interested in most of my power at the top end and lower C/R. I want to maximize torque at lower RPM. I'm looking for any input or suggestions.
The engine will be NA and I was thinking of using a 224R or 228R cam. Also, I'm thinking of using 243 heads to increase the C/R. I'm looking to get the C/R around 10.5:1 or close. What would the C/R be on unmilled 243's on an LQ4 with stock head gaskets? I'm figuring about 10.2:1. Would I also need to flycut the pistons or would they be ok?
Would the PRC Stage 2.5 LS6 heads or even the stage 1 heads be an option for what I'm looking for? I'm not saying money is no option, but if I can save to do it right the first time, I will be happier in the end.
Also, any idea what flywheel numbers might be?
The engine will be NA and I was thinking of using a 224R or 228R cam. Also, I'm thinking of using 243 heads to increase the C/R. I'm looking to get the C/R around 10.5:1 or close. What would the C/R be on unmilled 243's on an LQ4 with stock head gaskets? I'm figuring about 10.2:1. Would I also need to flycut the pistons or would they be ok?
Would the PRC Stage 2.5 LS6 heads or even the stage 1 heads be an option for what I'm looking for? I'm not saying money is no option, but if I can save to do it right the first time, I will be happier in the end.
Also, any idea what flywheel numbers might be?
As far as flycutting, it all depends on which cam and how it is spec'd. I didn't want to have to flycut, so i had Pat G spec me a cam out with that in mind. It's still about the size of an MS3, but no flycutting due to the custom valve events. An idea to keep in mind for you...
Thread Starter
Teching In
Joined: Feb 2011
Posts: 9
Likes: 0
I'm doing an LQ4 build now with PRC Stage 2.5 heads and a custom cam. My heads have been cleaned up to 62cc, and with a stock thickness head gasket the compression ratio is 10.55:1. I believe it is right around 10.3:1 with stock 64cc 243s and a stock thickness head gasket.
As far as flycutting, it all depends on which cam and how it is spec'd. I didn't want to have to flycut, so i had Pat G spec me a cam out with that in mind. It's still about the size of an MS3, but no flycutting due to the custom valve events. An idea to keep in mind for you...
As far as flycutting, it all depends on which cam and how it is spec'd. I didn't want to have to flycut, so i had Pat G spec me a cam out with that in mind. It's still about the size of an MS3, but no flycutting due to the custom valve events. An idea to keep in mind for you...
I would be guessing on numbers...especially since I'll be held back a bit using the LS6 intake manifold. I'm hoping for 450ish, but that may be too optimistic.
I'll look at my cam sheet from Pat G when I can find it, but I'm pretty sure the shift point will be right at 6700rpms. Not sure on the rpm power range. I've got 4.10 gears, so that played into the custom cam specs.
I would seriously encourage you to consider contacting Pat G for a custom cam and having it ground by EPS. I have yet to see anyone disappointed by going that route. He will take your input and your goals and spec a cam that is perfect for your setup. And for negligible cost...
I'll look at my cam sheet from Pat G when I can find it, but I'm pretty sure the shift point will be right at 6700rpms. Not sure on the rpm power range. I've got 4.10 gears, so that played into the custom cam specs.
I would seriously encourage you to consider contacting Pat G for a custom cam and having it ground by EPS. I have yet to see anyone disappointed by going that route. He will take your input and your goals and spec a cam that is perfect for your setup. And for negligible cost...
