LS7 Build Advice
Thread Starter
Instructor
Joined: Oct 2011
Posts: 151
Likes: 1
From: Texas
LS7 Build Advice
I am tossing around the idea of just building an LS7 for my project car. However, after a lot of reading and searching I just decided to toss up a thread with my own ideas for my setup.
I am going to start with a new, stock LS7 block from GM. The most this engine will get in mods will be a mild streetable cam with longtubes. Possibly worked heads but that isn't 100% right now. This car/motor will never see FI.
So, my question would be what upgrades would be best to make the LS7 more durable? I know I want to forge the pistons but would the stock crank & Ti rods be good enough? or should I go with a complete forged rotating assembly package? I know I would need to balance the assembly if I was to go with the stock crank/rods.
On the head, is there an upgrade for the valve guides? I believe I have read where it is good to upgrade the valves as well. I can search this subject if need be but figured I would ask while I am making this thread.
Thanks for any advice and I apologize in advance as I am sure there are 500 threads on this. I just couldn't find them all.
I am going to start with a new, stock LS7 block from GM. The most this engine will get in mods will be a mild streetable cam with longtubes. Possibly worked heads but that isn't 100% right now. This car/motor will never see FI.
So, my question would be what upgrades would be best to make the LS7 more durable? I know I want to forge the pistons but would the stock crank & Ti rods be good enough? or should I go with a complete forged rotating assembly package? I know I would need to balance the assembly if I was to go with the stock crank/rods.
On the head, is there an upgrade for the valve guides? I believe I have read where it is good to upgrade the valves as well. I can search this subject if need be but figured I would ask while I am making this thread.
Thanks for any advice and I apologize in advance as I am sure there are 500 threads on this. I just couldn't find them all.
Drifting
Joined: Oct 2011
Posts: 1,709
Likes: 16
From: pembroke pines (broward) florida
this is so broad. u can get huge power from an ls7 with high compression n chunky cam. wcch can fix the heads and mill them. set of high comp slugs and agressive cam will get things moving. rods/pistons/heads/cam will make it a very fun
Thread Starter
Instructor
Joined: Oct 2011
Posts: 151
Likes: 1
From: Texas
I understand it can be a broad subject but right now I am not looking for info on what size cam to go with or anything like that. I am mostly looking for advice on some things to do to help prevent some of the issues seen with the LS7.
I found a stock crank & Ti rods but some people say to go with a complete forge package / setup. I just wasn't sure if that is necessary for what my plans are. Also some advice on what to do to help prevent a valve from dropping / breaking on the stock LS7 heads.
Thanks
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
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What kind of car is it going in? First big decision is have you decided to do wet sump, or dry?
Based on your limited information, I would recommend going wet sump. Only block modification necessary would be having it drilled for a dipstick tube. Use an LS2 style crank (w/4" stroke) and front engine cover so you can use a non-LS7 oil pump. Drops right in.
Several choices on heads. Reworked OE or TSP LS7 heads for example.
Based on your limited information, I would recommend going wet sump. Only block modification necessary would be having it drilled for a dipstick tube. Use an LS2 style crank (w/4" stroke) and front engine cover so you can use a non-LS7 oil pump. Drops right in.
Several choices on heads. Reworked OE or TSP LS7 heads for example.
Thread Starter
Instructor
Joined: Oct 2011
Posts: 151
Likes: 1
From: Texas
It is going to be going into a 91 FC RX-7 so it will be getting converted over to a wet sump setup for sure. The car will not see a lot of track time. It will be used a lot for commuting / street and just to have some fun with.
I know the guides on the stock heads seem to be an issue so I want to take care of that issue as well.
There are so many different opinions on the forge subject. It seems that with a mild cam I would be fine only forging the pistons but then I have been told I should go forged with the entire rotating assembly.
I know the guides on the stock heads seem to be an issue so I want to take care of that issue as well.
There are so many different opinions on the forge subject. It seems that with a mild cam I would be fine only forging the pistons but then I have been told I should go forged with the entire rotating assembly.
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Thanks for the reply and info.
I understand it can be a broad subject but right now I am not looking for info on what size cam to go with or anything like that. I am mostly looking for advice on some things to do to help prevent some of the issues seen with the LS7.
I found a stock crank & Ti rods but some people say to go with a complete forge package / setup. I just wasn't sure if that is necessary for what my plans are. Also some advice on what to do to help prevent a valve from dropping / breaking on the stock LS7 heads.
Thanks
I understand it can be a broad subject but right now I am not looking for info on what size cam to go with or anything like that. I am mostly looking for advice on some things to do to help prevent some of the issues seen with the LS7.
I found a stock crank & Ti rods but some people say to go with a complete forge package / setup. I just wasn't sure if that is necessary for what my plans are. Also some advice on what to do to help prevent a valve from dropping / breaking on the stock LS7 heads.
Thanks
Contrary to popular opinion the LS7 is a very stout motor as I've been running one in my drag car since 2008. I have had a couple failures during that time but one was due to a dropped valve (my fault as I stupidly didn't have my valve guides replaced on the replacement heads I had just installed) and the other time it was due to a cracked sleeve but that was after almost 600 track passes.
Forged parts are nice but you'd be surprised at the kind of abuse the stock parts will take. I'm running low 10's right now with stock injectors, rods, crank, pistons, unported heads and intake manifold.
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