"Stock" Engine Ideas for New Project
12-22-2011, 11:30 PM
#1
"Stock" Engine Ideas for New Project I'm thinking of parting ways with the GTO in order to pick up a Viper next year. In the mean time, I still want a fun LS based vehicle.
Enter my 1999 Silverado RCSB Z71 daily driver
The truck has ~130k miles on it. I'm already planning the 4L80e swap so the drivetrain will be set.
I'm going to build a one off front mount turbo kit for it similar to how I did the GTO. I will most likely even run the same turbo since I'm loving how this PT7875 is treating me. I'm also considering a S475 given I have tons of space and it's half the price. Turbo LS in a 4 wheel drive "light" truck should hold me over
Anyways, now I'm thinking about the engine. My initial thought was just to boost the stock 4.8L and let her eat. Guys have been making plenty of power on these motors with little to zero mods. I have E85 available all over up here so I can run it and will run it if need be.
This is what got me thinking of putting together a different motor for it. I have a few LQ4s laying around. I was thinking of finding a stock LS2 rotating assembly and swapping it into my LQ4 block. I could run my 4.8L 706 heads which should give me over 11:1 compression I believe. Compression plus E85 and boost sounds like fun I'm not terribly worried about the smaller intake runner and valve on the 706s due to going FI. I believe the exhaust side is still the same size as all the other LS heads.
The high compression coupled with boost, E85 and a decently strong lower end from the LS2 should give me a pretty stout and cheap little motor.
So, here's the question. Would it be worth running the 6L or just stick with the stock 4.8L? Any idea what kind of power I could get out of the 6L described above with just say an LS6 cam and no boost? I would think 430hp or so shouldn't be out of the question on good fuel.
Thoughts and opinions welcome This project won't start until March and should only take about 4 weeks to get together.
Enter my 1999 Silverado RCSB Z71 daily driver
The truck has ~130k miles on it. I'm already planning the 4L80e swap so the drivetrain will be set.
I'm going to build a one off front mount turbo kit for it similar to how I did the GTO. I will most likely even run the same turbo since I'm loving how this PT7875 is treating me. I'm also considering a S475 given I have tons of space and it's half the price. Turbo LS in a 4 wheel drive "light" truck should hold me over
Anyways, now I'm thinking about the engine. My initial thought was just to boost the stock 4.8L and let her eat. Guys have been making plenty of power on these motors with little to zero mods. I have E85 available all over up here so I can run it and will run it if need be.
This is what got me thinking of putting together a different motor for it. I have a few LQ4s laying around. I was thinking of finding a stock LS2 rotating assembly and swapping it into my LQ4 block. I could run my 4.8L 706 heads which should give me over 11:1 compression I believe. Compression plus E85 and boost sounds like fun
I'm not terribly worried about the smaller intake runner and valve on the 706s due to going FI. I believe the exhaust side is still the same size as all the other LS heads.The high compression coupled with boost, E85 and a decently strong lower end from the LS2 should give me a pretty stout and cheap little motor.
So, here's the question. Would it be worth running the 6L or just stick with the stock 4.8L? Any idea what kind of power I could get out of the 6L described above with just say an LS6 cam and no boost? I would think 430hp or so shouldn't be out of the question on good fuel.
Thoughts and opinions welcome
This project won't start until March and should only take about 4 weeks to get together. 
12-23-2011, 11:24 AM
#3
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If you switch out the internals I would run 317s. I believe lq4 have the dished pistons and they are rated at a 9.4-9.6 compression with the 317s. You could get a 10.1 or better with 317s. They flow better are cheap and you could get the low end you want as well.
Or you could just put a set of 243s on one of the lq4s. That could bring compression up since there is almost 10cc difference between 317s and 243s.
Do you mean 430fwhp or 430rwhp? I think you'd be hard pressed to put that down since the ls2 specs are similar to what you have in mind.
Maybe look in to a 5.3? They can put down crazy numbers in stock form with minor adjustments.
Don't know what you budget is so that's why i suggested other stuff as well.
Or you could just put a set of 243s on one of the lq4s. That could bring compression up since there is almost 10cc difference between 317s and 243s.
Do you mean 430fwhp or 430rwhp? I think you'd be hard pressed to put that down since the ls2 specs are similar to what you have in mind.
Maybe look in to a 5.3? They can put down crazy numbers in stock form with minor adjustments.
Don't know what you budget is so that's why i suggested other stuff as well.
12-23-2011, 11:44 AM
#4
243s would be the best choice since they are almost as tight as the 706s but will flow better I suppose.
Budget isn't really an issue, I'm just trying to have some fun with stuff that I have laying around. I thought it would be kinda neat to go really high on the compression since I can run E85.
Basically, my idea was a higher than stock compression "LS2- Iron Block Hybrid" haha. Oh and I was talking fwhp.
Budget isn't really an issue, I'm just trying to have some fun with stuff that I have laying around. I thought it would be kinda neat to go really high on the compression since I can run E85.
Basically, my idea was a higher than stock compression "LS2- Iron Block Hybrid" haha. Oh and I was talking fwhp.
12-23-2011, 12:26 PM
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Sounds like a fun project. I would try to swing the 243s and ls6 cam. That will get you at least 400fwhp while maintaining around a 10.5:1 compression. I think the smaller intake valve on the 706s will kill any chances to make 400+ fwhp. If you have them you could get the 706s fitted for the stock 2.00 valves depending on cost if you are set and want to use them. That would help them flow more while allowing you to use what you got.
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12-24-2011, 09:52 PM
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I am an E85 fan and have recently finished running a 498 on E85. 13.1 compression. E85 loves compression and even though that is high compression for a boosted application I bet with the E85 you would be fine. It would be a killer combo!
