LS1 ThirdGen Questions
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Teching In
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LS1 ThirdGen Questions I've been contemplating making the ThirdGen LS1 swap for about a year now and have a few questions before I get started. Ive also been considering building a budget 427 using the Darton Wet sleeve system but I'm not too serious about it now. I appreciate any advice which will make this swap as painless as possible.
1. What modifications are needed to make the heater hose connection at the firewall if any?
2. What is the verdict on the coil packs issue. Some say they interfere with the heater box while others seem to have no problem at all.
3. What is required to convert the A/C to be used in the older ThirdGen?
4. What are the typical horsepower gains and gas mileage seen using the Darton sleeves with a moderate cam?
5. Will the stock T56 trans hold up to the power delivered by the 427?
Thanks again for any advice yall might have. Granted I'm almost a year away from making the swap, I would like to have a solid plan and all of my bases covered before I start investing serious time and money. I realize there are going to be some unexpected setbacks but would like to minimize them before hand.
1. What modifications are needed to make the heater hose connection at the firewall if any?
2. What is the verdict on the coil packs issue. Some say they interfere with the heater box while others seem to have no problem at all.
3. What is required to convert the A/C to be used in the older ThirdGen?
4. What are the typical horsepower gains and gas mileage seen using the Darton sleeves with a moderate cam?
5. Will the stock T56 trans hold up to the power delivered by the 427?
Thanks again for any advice yall might have. Granted I'm almost a year away from making the swap, I would like to have a solid plan and all of my bases covered before I start investing serious time and money. I realize there are going to be some unexpected setbacks but would like to minimize them before hand.
TECH Fanatic
Joined: Aug 2003
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From: Newport News, Va
Originally Posted by philedw1019
I've been contemplating making the ThirdGen LS1 swap for about a year now and have a few questions before I get started. Ive also been considering building a budget 427 using the Darton Wet sleeve system but I'm not too serious about it now. I appreciate any advice which will make this swap as painless as possible.
1. What modifications are needed to make the heater hose connection at the firewall if any?
2. What is the verdict on the coil packs issue. Some say they interfere with the heater box while others seem to have no problem at all.
3. What is required to convert the A/C to be used in the older ThirdGen?
4. What are the typical horsepower gains and gas mileage seen using the Darton sleeves with a moderate cam?
5. Will the stock T56 trans hold up to the power delivered by the 427?
Thanks again for any advice yall might have. Granted I'm almost a year away from making the swap, I would like to have a solid plan and all of my bases covered before I start investing serious time and money. I realize there are going to be some unexpected setbacks but would like to minimize them before hand.
1. What modifications are needed to make the heater hose connection at the firewall if any?
2. What is the verdict on the coil packs issue. Some say they interfere with the heater box while others seem to have no problem at all.
3. What is required to convert the A/C to be used in the older ThirdGen?
4. What are the typical horsepower gains and gas mileage seen using the Darton sleeves with a moderate cam?
5. Will the stock T56 trans hold up to the power delivered by the 427?
Thanks again for any advice yall might have. Granted I'm almost a year away from making the swap, I would like to have a solid plan and all of my bases covered before I start investing serious time and money. I realize there are going to be some unexpected setbacks but would like to minimize them before hand.
But that dosent mean I cant help you
OK, First Off with the 427, this setup will put a pretty big hole in your pocket...This setup has cost many people $20000+ Not only because of the motor, but factor in labor, machining, etc....Also, your gonna need a rear end, beefed up tranny, chassis mods, etc so that your car will handle the power....
Now to your questions...I can answer a few....
2) I dont know much about it, but you can buy a coil pack relocation kit, where you can mount them somewhere else(I.E. Firewall)..Another option is to get LS1 TRUCK coil packs, these allow more clearence...
3) To use your A/C Compressor from your third gen you can buy here at Fbody Motorsports. Ive heard of fabrication, but for me Id rather pay the price than deal with fabrication...
4) Cant really tell you much, but LS1s get GREAT gas mileage, specially with the T56(2 OD gears)
5) The T56 will need to be built with some Hi-Performance parts(I.E. Clutches)
Also, check out this page
They have alot of stuff for the LS1 swap...
Hope this helps....
Good Luck
Thread Starter
Teching In
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Thanks Thanks for the info. I have owned a fourth gen (LT1) and a third gen and i know on the fourth gen the heater hose is rather complex and not easily modified so I'm not sure how I should go about making the connections but thats not a big problem.
Also, I checked out that A/C compressor bracket you mentioned and that opened up a few more questions
If I reused the old compressor, would i still have to notch the crossmember since it appears to be mounted up top? That would be a serious selling point if it allowed me to bypass that step.
Thanks again and I'll probably be adding more questions as they come up
Also, I checked out that A/C compressor bracket you mentioned and that opened up a few more questions
If I reused the old compressor, would i still have to notch the crossmember since it appears to be mounted up top? That would be a serious selling point if it allowed me to bypass that step.Thanks again and I'll probably be adding more questions as they come up
TECH Fanatic
Joined: Aug 2003
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From: Newport News, Va
Post them as they come up...Ill try my best to answer them 
I beleive(Not totally sure) that you WONT have to noch it If you use the thirdgen AC Compressor....But If you do use the LS1 Compressor you WILL have to notch it
Have you bought the LS1/T56 yet?? If not, you can probably find one that comes with the LS1 Compressor...
I beleive(Not totally sure) that you WONT have to noch it If you use the thirdgen AC Compressor....But If you do use the LS1 Compressor you WILL have to notch itHave you bought the LS1/T56 yet?? If not, you can probably find one that comes with the LS1 Compressor...
