LS3 into 4th gen oil pan nightmare
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Joined: Mar 2012
Posts: 158
Likes: 15
From: fbg, tx
Are yall ******* kidding? The ls1 block and the ls3 block are the same except for bore size and maybe reinforcement. You can literally bolt up an ls3 into a camaro using all the camaro parts on the ls3. Like is this guy joking?
Agreed, I used a new pump on mine anyway cause I had an L92, new pump, fbody pan, windage tray and I threw in a trap door from improved racing, been running over 5 years now.
Ls3 pump is reversed from the ls1 and the pickup will absolutely not work, and cannot be modified to work.
Talked to a guy at summit racing, " something Fletcher", and he said this was a common surprise for people doing this very swap.
They offer a special pan, windage tray, pick-up and dip stick kit to address this very issue.
Not cheap, $602.00, but it is what it is.
This does not apply for people who have a tubular k-frame in their 4thg gen
Talked to a guy at summit racing, " something Fletcher", and he said this was a common surprise for people doing this very swap.
They offer a special pan, windage tray, pick-up and dip stick kit to address this very issue.
Not cheap, $602.00, but it is what it is.
This does not apply for people who have a tubular k-frame in their 4thg gen
https://ls1tech.com/forums/pontiac-f...-trans-am.html
Regarding the oil pump, @Chev70elle
I’d like to see pictures of the LS1 pump compared to the LS3 pump. I’ve never known of a reversed pump for the LS series engines. Heck…use your LS1 pump on the LS3.
You can't.
Pickup tube is on the wrong side.
So the LS3 pan will not clear the k-member.
The ls1 pan WILL fit on the ls3, but you cant use the ls1 pick up tube, as the inlet is on the opposite side.
And you can't use the ls3 pickup as the ls1 windage tray blocks it.
And you cant use the ls1 windage tray as the ls3 pickup wont clear it.
I wish i would have taken a video so i could show you what I am talking about, but i am done for the day and can.t get back to it until Monday afternoon.
By then, hopefully, my new setup will be here.
Thank you guys for your attention in this
Pickup tube is on the wrong side.
So the LS3 pan will not clear the k-member.
The ls1 pan WILL fit on the ls3, but you cant use the ls1 pick up tube, as the inlet is on the opposite side.
And you can't use the ls3 pickup as the ls1 windage tray blocks it.
And you cant use the ls1 windage tray as the ls3 pickup wont clear it.
I wish i would have taken a video so i could show you what I am talking about, but i am done for the day and can.t get back to it until Monday afternoon.
By then, hopefully, my new setup will be here.
Thank you guys for your attention in this
Glad you said that, so stop arguing and listen to us who have done this MUCH more than you.
But with my friend who is a mechanic by trade over the course of 20 years, has installed two different sets of headers, two different torque converters, two different cams, cylinder heads, strange 12 bolt rear and other odds and ends.
It is entirely possible that the answer is right in front of me, but I am overthinking it and cant see it.
Like looking for your keys when they are in your pocket
It is entirely possible that the answer is right in front of me, but I am overthinking it and cant see it.
Like looking for your keys when they are in your pocket
I wouldn't be bragging about his 20 years with that little amount of experience.
Now, as mentioned above, take some PICTURES of what you are looking at because myself as well as others commenting here have seen and done enough to where we've bolted together Engines and got our cars running. From what I've seen and even some google research the LS3 Factory Oil Pump is the same style as the LS1 Oil Pump, which is the same for most Gen III and Gen IV LS Engines. Why we are all really wondering what the issue is here.
So for the third time instead of constant back and forth of chasing your tail and we are all wrong..... PICTURES.
Until then nothing more really to say until we all see what's going on.
Every LS3 Block I've seen looks like this, google generic pic but still they look like this, bolted up the Melling 295 Pump up to it fine and the LS1 Fbody stuff bolts on from there..
Last edited by the_merv; Jul 12, 2025 at 10:22 AM.
I'm in for entertainment at this point. This one is pretty good..
Lol. It worked on your LS1…it will work on your LS3. They are exactly the same engine on the bottom, minus bore size. Exactly. The. Same. Cranks are the same. Your friend is wrong. I build performance LS engines…lots of them. There is no nightmare here. It’s easy peasy.
Using a LS3 ALUMINUM engine in my 02 FBODY
Melling 10295 LS oil pump
Factory oil pan
Factory Pickup
Factory Windage tray
Not sure why you are having issues... 5k miles on my setup with zero issues.
Lol. It worked on your LS1…it will work on your LS3. They are exactly the same engine on the bottom, minus bore size. Exactly. The. Same. Cranks are the same. Your friend is wrong. I build performance LS engines…lots of them. There is no nightmare here. It’s easy peasy.
You said this came out of a corvette. Is this a dry sump engine by chance? As everyone else has said the ls3 can accept all the ls1 parts and as proof, GM did that with the LS3 crate engines. They all came with the fbody oil pan and oil pump you are trying to make work here but if it was a dry sump engine (I think the manual ls3 c6's came with it anyway), it wouldn't fit.
TECH Senior Member
Joined: Jun 2016
Posts: 22,288
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From: Central Cal.
I don't build engines, as some here have had to remind me.
BUT, I DO know enough about LS engines to know for sure that they're nearly IDENTICAL in construction.
YES, oil pumps MIGHT be different capacity, or not, but THEY INTERCHANGE, except for dry sump engines.
If used as coordinated pairs, pans and pickup tubes INTERCHANGE, again, dry sumps being the exception.
With the exception of the 4.8's and the LS7, ALL cranks are the same stroke!
WHAT is the OP's issue here??
STILL shaking my head over this thread.... LOL!
BUT, I DO know enough about LS engines to know for sure that they're nearly IDENTICAL in construction.
YES, oil pumps MIGHT be different capacity, or not, but THEY INTERCHANGE, except for dry sump engines.
If used as coordinated pairs, pans and pickup tubes INTERCHANGE, again, dry sumps being the exception.
With the exception of the 4.8's and the LS7, ALL cranks are the same stroke!
WHAT is the OP's issue here??
STILL shaking my head over this thread.... LOL!
Last edited by G Atsma; Jul 13, 2025 at 09:35 AM.
Dry Sump Engine does have a longer Crank too, the snout is longer. That complicates things as well.
That's why I've been adamant about wanting pics of what this guy has so we can verify what it is and move forward from there.
Yes, some of the LS3 Corvettes could be ordered that way. There's a few things on the Engine to where you can tell the difference without getting into it.
Just pass it along and don't be that guy who takes a double hit.. 
That's why I've been adamant about wanting pics of what this guy has so we can verify what it is and move forward from there.
Yes, some of the LS3 Corvettes could be ordered that way. There's a few things on the Engine to where you can tell the difference without getting into it.
Last edited by the_merv; Jul 12, 2025 at 04:55 PM.
Thread Starter
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Joined: Oct 2005
Posts: 1,131
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From: olympia, wash
Here are the pictures you guys asked for.
As you can see, it is the ls1 pan windage tray and pickup from my old engine.
And you can see the very visible gap when I tried to fit it on my ls3
As you can see, it is the ls1 pan windage tray and pickup from my old engine.
And you can see the very visible gap when I tried to fit it on my ls3
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Joined: Oct 2002
Posts: 2,785
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From: Mefis
Take the LS3 winage tray off the LS3 engine. That's your problem. The one off an LS1 is shorter, when I say shorter I mean it doesn't go the whole length of the block. It stops where the LS1 gets shallow. Switch the windage trays . Use the LS1 pan and pick-up tube. It's simple as that.
Thread Starter
TECH Fanatic
Joined: Oct 2005
Posts: 1,131
Likes: 76
From: olympia, wash
Take the LS3 winage tray off the LS3 engine. That's your problem. The one off an LS1 is shorter, when I say shorter I mean it doesn't go the whole length of the block. It stops where the LS1 gets shallow. Switch the windage trays . Use the LS1 pan and pick-up tube. It's simple as that.