Need some help on Frankensteining a LS3/LS1
01-02-2018, 12:53 PM
#1
Need some help on Frankensteining a LS3/LS1 Sorry if this may seem simple to some, I just want some confirmation from others. Can I use my Speed Inc LS1 cam in a LS3 shortblock?
Here is the scenario... 2004 GTO, engine spun a rod bearing 500 miles after I bought the car, but I liked the drive ability of the cam considering the little time I drove it.
I also have a 2010 Camaro SS making 800+rwhp on stock LS3 shortblock with a 7675. I figured if I need to buy a new bottom end, whey spend the money on the GTO when the Camaro is the one running FI.
So I yanked out the LS3 engine from my 2010 Camaro and will be putting that in the GTO (just the shortblock). I want to reuse the LS1 speedinc cam, LS6 ported heads, and FAST 90/90 setup that was on the GTO previously.
I was under the impression that I can use the LS1 cam, but I need an LS3 3 bolt timing set and front timing cover with a cam sensor. In addition, I need a valley cover to delete the knock sensors from that location, and mount them elsewhere. therefor the harness for the both the cam sensor and knock sensors will need to be lengthened (or by a plug an dplay kit).
I will also need the Ligenfelter 58x to 24x box.
Is this info accurate? Anything else that I am missing?
Here is the scenario... 2004 GTO, engine spun a rod bearing 500 miles after I bought the car, but I liked the drive ability of the cam considering the little time I drove it.
I also have a 2010 Camaro SS making 800+rwhp on stock LS3 shortblock with a 7675. I figured if I need to buy a new bottom end, whey spend the money on the GTO when the Camaro is the one running FI.
So I yanked out the LS3 engine from my 2010 Camaro and will be putting that in the GTO (just the shortblock). I want to reuse the LS1 speedinc cam, LS6 ported heads, and FAST 90/90 setup that was on the GTO previously.
I was under the impression that I can use the LS1 cam, but I need an LS3 3 bolt timing set and front timing cover with a cam sensor. In addition, I need a valley cover to delete the knock sensors from that location, and mount them elsewhere. therefor the harness for the both the cam sensor and knock sensors will need to be lengthened (or by a plug an dplay kit).
I will also need the Ligenfelter 58x to 24x box.
Is this info accurate? Anything else that I am missing?
01-02-2018, 12:56 PM
#2
Sound like you've covered all the bases....just gotta drill larger and tap the LS3 knock sensor holes on the sides of the block for the larger LS1 KS
And that heads cam combo will love the extra cubic inches.....IMO
not perfect but should work well if expectations are realistic
And that heads cam combo will love the extra cubic inches.....IMO
not perfect but should work well if expectations are realistic
01-02-2018, 02:06 PM
#4
The LS1 pcm uses one wire knock sensors. The LS3 uses a 2 wire sensor.
The LS1 PCM needs the stock sensors.
As was mentioned, you will need to mount them on the side of the block and get some sort of harness extension.
Even at that, the signal won’t be the same as if they were under the valley. So you might have to work with the sensitivity.
Your present cam will work fine. So will the heads.
you are correct on needing the right gear front cover and another extension harness.
Should run well!
Ron
The LS1 PCM needs the stock sensors.
As was mentioned, you will need to mount them on the side of the block and get some sort of harness extension.
Even at that, the signal won’t be the same as if they were under the valley. So you might have to work with the sensitivity.
Your present cam will work fine. So will the heads.
you are correct on needing the right gear front cover and another extension harness.
Should run well!
Ron
01-02-2018, 09:10 PM
#6
The one wild card is the ported 243's. I am looking to be in the 68-70cc chamber size, and I am not sure where these are at, or what can they be opened up to. I believe 64cc chambers on the LS3 shortblock will yield somewhere in the 11.3-11.4 SCR... and I want to be in the 10.7-10.8 SCR in case I throw some boost at this down the road. If these cathedrals can't be opened up to the cc's I want, then they will sold with FAST 90/90 and CNC LS3's will go on.
Last edited by RealQuick; 01-02-2018 at 09:18 PM.
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01-03-2018, 09:55 AM
#8
The one wild card is the ported 243's. I am looking to be in the 68-70cc chamber size, and I am not sure where these are at, or what can they be opened up to. I believe 64cc chambers on the LS3 shortblock will yield somewhere in the 11.3-11.4 SCR... and I want to be in the 10.7-10.8 SCR in case I throw some boost at this down the road. If these cathedrals can't be opened up to the cc's I want, then they will sold with FAST 90/90 and CNC LS3's will go on.
01-03-2018, 10:08 AM
#10
If I were you, I'd leave them on while you drive around NA and enjoy the extra power from the compression. When you go to boost it, pull them off and sell them, then swap on some stock 317 heads to lower the compression. You can open the 243 chamber to a larger volume, but if you go to resell them, you might have a hard time finding someone interested in them because of it.
Since I am putting two motors in two cars, I'd prefer to do the heads once on the GTO.
If resale is going to be an issue, then maybe I should just go LS3 top end now.