LS6 swap with 4L70E into 1981 Corvette
01-28-2009, 11:12 PM
#1
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Thread Starter
Need help with LS6 swap with 4L70E into 1981 Corvette
I need as much help and info as possible. I plan to swap in an LS6 (dyno'd at 505 HP) into a 1981 Corvette and mate it to a 4L70E automatic. Both purchased separately. Where is the best place to get engine conversion mounting plates? Does anyone make a header for a C3 with an LS motor in it. If anyone (I know there are lots out there) who has done an LS swap into a C3 that can provide details, pictures, short cuts, what I need to look for bracket wise. What's I'll need for ECM and tranny module. Anything and everything would be appreciated. Right now I have a roller 406 CID mated to a 700R4 and 4:11 gears. It's a rocket now, anyone need a 406 CID? Do you think the 4:11's will be too much gear? I have a set of 3:73's as well.
Last edited by 81Wayne; 01-28-2009 at 11:20 PM.
01-29-2009, 12:55 AM
#2
Safety Car
Did you get a chance to read the sticky on the C3 tech page at the top which covers the LS install issues into a C3?
http://forums.corvetteforum.com/c3-t...-their-c3.html
Also check out Z069 thread:
http://forums.corvetteforum.com/c3-t...this-time.html
Also there was someone selling a set of LS header for a C3 on the for sale section a short while back 1-2 months. Didnt seem like they had sold not sure.
http://forums.corvetteforum.com/c3-t...-their-c3.html
Also check out Z069 thread:
http://forums.corvetteforum.com/c3-t...this-time.html
Also there was someone selling a set of LS header for a C3 on the for sale section a short while back 1-2 months. Didnt seem like they had sold not sure.
01-29-2009, 07:34 AM
#3
Le Mans Master
I run an LS6 with a T56 in my 81 but I used an aftermarket chassis. AS suggested, go through the links above Others have done it.
The 4:11's might be a little steep with the Automatic but I don't know the gearing on the auto. If it were a 6speed I'd tell you you are fine. I'd check around but it also depends on how and where you drive the car.
Check with SpeedHound for one (Forum Member and website at http://www.speedhound.com/). He supplies engine plates and headers for these conversions. I'd also recommend an aftermarket engine harness if you can't wire your own. It's much easier, but not cheaper, to buy an aftermarket pulley system. OThers have used F-Body components or fabbed up something. Again, the threads linked above will help with that.
Although a little different I have some info on my website that might help and give you a few ideas.
Good luck.
FrankenSport Build
The 4:11's might be a little steep with the Automatic but I don't know the gearing on the auto. If it were a 6speed I'd tell you you are fine. I'd check around but it also depends on how and where you drive the car.
Check with SpeedHound for one (Forum Member and website at http://www.speedhound.com/). He supplies engine plates and headers for these conversions. I'd also recommend an aftermarket engine harness if you can't wire your own. It's much easier, but not cheaper, to buy an aftermarket pulley system. OThers have used F-Body components or fabbed up something. Again, the threads linked above will help with that.
Although a little different I have some info on my website that might help and give you a few ideas.
Good luck.
FrankenSport Build
01-29-2009, 04:05 PM
#4
Advanced
Thread Starter
I run an LS6 with a T56 in my 81 but I used an aftermarket chassis. AS suggested, go through the links above Others have done it.
The 4:11's might be a little steep with the Automatic but I don't know the gearing on the auto. If it were a 6speed I'd tell you you are fine. I'd check around but it also depends on how and where you drive the car.
Check with SpeedHound for one (Forum Member and website at http://www.speedhound.com/). He supplies engine plates and headers for these conversions. I'd also recommend an aftermarket engine harness if you can't wire your own. It's much easier, but not cheaper, to buy an aftermarket pulley system. OThers have used F-Body components or fabbed up something. Again, the threads linked above will help with that.
Although a little different I have some info on my website that might help and give you a few ideas.
Good luck.
FrankenSport Build
The 4:11's might be a little steep with the Automatic but I don't know the gearing on the auto. If it were a 6speed I'd tell you you are fine. I'd check around but it also depends on how and where you drive the car.
Check with SpeedHound for one (Forum Member and website at http://www.speedhound.com/). He supplies engine plates and headers for these conversions. I'd also recommend an aftermarket engine harness if you can't wire your own. It's much easier, but not cheaper, to buy an aftermarket pulley system. OThers have used F-Body components or fabbed up something. Again, the threads linked above will help with that.
Although a little different I have some info on my website that might help and give you a few ideas.
Good luck.
FrankenSport Build
01-29-2009, 06:03 PM
#6
Drifting
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Did a little research.. Seems that the 4L70E is stronger version of the 700R4/4L60/4L60E. Your first gear is pretty steep (3.06 X 4.11 = 12.56:1). You probably find your current first gear practically useless, and with a more powerful engine that will be even more the case. If decide to sell the 4.11s... I am a potential buyer.
01-29-2009, 09:42 PM
#8
Melting Slicks
I can't imagine the power of an LS6 in a C3...how does it handle the power...what did you do for the "whoa" after you added the "go"? 
I know a guy that put an LS7 in a 65...has a C4 Street Shop frame under it...amazing car! I admire what you guys have done merging the old with the new!
I know a guy that put an LS7 in a 65...has a C4 Street Shop frame under it...amazing car! I admire what you guys have done merging the old with the new!
01-29-2009, 10:44 PM
#9
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Thread Starter
Did a little research.. Seems that the 4L70E is stronger version of the 700R4/4L60/4L60E. Your first gear is pretty steep (3.06 X 4.11 = 12.56:1). You probably find your current first gear practically useless, and with a more powerful engine that will be even more the case. If decide to sell the 4.11s... I am a potential buyer.
01-29-2009, 11:30 PM
#10
Le Mans Master
I can't imagine the power of an LS6 in a C3...how does it handle the power...what did you do for the "whoa" after you added the "go"?
I know a guy that put an LS7 in a 65...has a C4 Street Shop frame under it...amazing car! I admire what you guys have done merging the old with the new!
I know a guy that put an LS7 in a 65...has a C4 Street Shop frame under it...amazing car! I admire what you guys have done merging the old with the new!
The Whoa (Corvette C4 Suspension and Brakes):
And a little hydraulic brake boost power:
Kinda like a slot car on rails:
01-29-2009, 11:58 PM
#12
Safety Car
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Yeah, Joe has set the bar pretty high when it comes to a LS conversion. The only car I've seen show the same level of detail as his was this one at the World of Wheels this year in Boston:
I think pics of the frame of this car might be somewhere in the LS swap thread.
Remember that the LS engines are quite a bit lighter than the iron block engines so the stock C3 brakes should work very well if they are in good working order. 4-piston calipers were very advanced technology for the 60's and 70's and only very expensive European cars use anything other than single-piston floating calipers these days.
Rick B.
I think pics of the frame of this car might be somewhere in the LS swap thread.
Remember that the LS engines are quite a bit lighter than the iron block engines so the stock C3 brakes should work very well if they are in good working order. 4-piston calipers were very advanced technology for the 60's and 70's and only very expensive European cars use anything other than single-piston floating calipers these days.
Rick B.
01-30-2009, 12:16 AM
#13
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Thread Starter
01-30-2009, 12:22 AM
#14
Advanced
Thread Starter
Did a little research.. Seems that the 4L70E is stronger version of the 700R4/4L60/4L60E. Your first gear is pretty steep (3.06 X 4.11 = 12.56:1). You probably find your current first gear practically useless, and with a more powerful engine that will be even more the case. If decide to sell the 4.11s... I am a potential buyer.
01-30-2009, 06:48 AM
#15
Le Mans Master
Yeah, Joe has set the bar pretty high when it comes to a LS conversion. The only car I've seen show the same level of detail as his was this one at the World of Wheels this year in Boston:
I think pics of the frame of this car might be somewhere in the LS swap thread.
Remember that the LS engines are quite a bit lighter than the iron block engines so the stock C3 brakes should work very well if they are in good working order. 4-piston calipers were very advanced technology for the 60's and 70's and only very expensive European cars use anything other than single-piston floating calipers these days.
Rick B.
I think pics of the frame of this car might be somewhere in the LS swap thread.
Remember that the LS engines are quite a bit lighter than the iron block engines so the stock C3 brakes should work very well if they are in good working order. 4-piston calipers were very advanced technology for the 60's and 70's and only very expensive European cars use anything other than single-piston floating calipers these days.
Rick B.
That's Rich and Barb Lagasses 63 and the entire build can be seen at:
http://www.richsclassiccorvettes.com/
They are great people and we had the opportunity to spend the week with them at Carlisle this year in the Chip's Choice display. Rich is always willing to help so if anyone were doing a conversion, he's paved the way.
Joe..
01-30-2009, 05:37 PM
#17
Drifting
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Correct it's a stronger electronic version of the 700R4 I currently have. Although the 700R4 I have now was built Server duty and dyno tested to over 9,000 RPM's. Right now if I stand on it at 30 MPH, it'll down shift to 2nd then it'll shift at 5800 RPM and chirp the tires into 3rd gear. I have a line-loc, within 30 seconds the tire smoke is so intense the car disappears with my current 406CID carb motor.
01-30-2009, 05:54 PM
#18
Melting Slicks
...but that's slightly more than just an LS6 swap!Here are some pics of the LS7 powered 65 I mentioned above. These shots were from our annual Toys for Tot's display inside the local mall, Dec 2007. We paried it beside an NCRS restored 65, 396 car...quite the contrast
01-31-2009, 10:53 AM
#19
Racer
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Joe's car is killer! I hope to see it the next time I visit Empire Automotive in New Windsor (the shop that built my Pro Touring '71 Cuda) which is across the Hudson bridge from Newburgh. Joe - you should take a ride over there and check out their 1300 HP, 1300 LB-FT twin turbo Dart which was debuted at PRI in December. It was a hit and will be featured in Popular Hot Rodding this year.
About Rich Lagasse's car, that car is in a class all by its self. The only car even remotely close to it *might* be the '62 car built before it.
Both of these cars have undergone immense detailing: grinding every weld on the entire frame, polishing every part - every bolt head, washer, nut, the entire T56 6-speed case. There are many thousands of hours of labor in polishing alone.
It doesn't take anything away from all of the other cars. I just don't think you will see another car built to that level for years to come. Rich said that was his last one at the level.
Yesterday, I sold a Stage 2 Pro Touring A-41 to a fellow with the SRTIII frame with LS7. He went PaddleShift, DualMode, etc. We should see his car on the circuit this year also. Joe's car and his car will make a killer pair of Vette Rods at Carlisle.
01-31-2009, 11:01 AM
#20
Racer
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Keisler stage 2 a-41
81Wayne,
For any LS engine putting out 550 HP or more, I recommend the Stage 2 A-41 PerfectFit kit ($4295). The included stall converter will come on at 2000rpm@500LB-FT, and the next step up converter (+$90) will come on at 2400rpm@500 LB-FT. All converters we carry are rated for 700 LB-FT.
The PerfectFit kit has everything needed to make the swap, down to the LS bell, LS flexplate, OD shifter gate and lens, crossmember, driveshaft, cooler lines, plug-'n-play computer, wiring harness, TPS sensor and cable, Mobile 1 Synthetic oil - every single part.
Here is a link to it.
For any LS engine putting out 550 HP or more, I recommend the Stage 2 A-41 PerfectFit kit ($4295). The included stall converter will come on at 2000rpm@500LB-FT, and the next step up converter (+$90) will come on at 2400rpm@500 LB-FT. All converters we carry are rated for 700 LB-FT.
The PerfectFit kit has everything needed to make the swap, down to the LS bell, LS flexplate, OD shifter gate and lens, crossmember, driveshaft, cooler lines, plug-'n-play computer, wiring harness, TPS sensor and cable, Mobile 1 Synthetic oil - every single part.
Here is a link to it.
