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I was wanting to do an auto conversion on my 2004 CTS-V but decided to sell it and build this instead.
i found a perfectly good running/driving shifting rust free 2008 CTS with 120K miles
Three days later I found a wrecked 2008 Pontiac G8 GT and bought the engine/trans harness and all the goodies
Here's the empty engine bay with CTS-V front sway bar and heater core coolant hoses. The stock CTS sway bar was in the way for the extra two cylinders. The CTS-V1 heater core coolant hoses fit perfect.
Engine going in for another mock up. CTS-V oil pan and engine brackets are used for the swap
6L80 trans fit pretty good. Had to customize the tunnel some what for more clearance. Some dynamat hides the fab work
The 6L50 and 6L80 are the exact same length. Only a conversion bracket was made. And some 3/8" aluminum stock to bring the output centerline back into alignment. You can also see the front half of the G8 driveshaft mated to the CTS rear half.
CTS-V1 and V2 exhaust manifolds are the same so either can be used, only V2 catalytic converters will fit.
V2 headers could also be used. V1 and V2 A/C pumps are the same but mounting brackets are different
along with the A/C hoses. The CTS ABS unit is right in the way of the A/C compressor. This had to be moved
because i was not going to drive a cadillac without A/C.
This is where things get a little tricky. V2 A/C hoses won't fit with the ABS unit right in the way so a V1 suction hose was used.
it was modified near the firewall because GM decided to swap the lines at the evaporator. A V1 discharge hose was used. It was modified on one end to fit the CTS-2 condenser. Both of these hoses are discontinued from GM. all custom transmission
lines, power steering lines, battery cables, radiator hoses, brackets, etc. are used and expect this to take up all available space and the most time to figure out. The harness is mostly from the donor vehicle but is grafted into the CTS fuse box,
BCM and ABS unit.
this swap is 98% complete.
Using a stock LS3 camshaft this engine should make a reliable 400/400
2006-7 CTS-V (LS2) engine cover fis L76 engine perfectly.
i may change the air intake tube, The flexible tube looks a little chinchy
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Last edited by LS BRAVADA; Sep 4, 2019 at 10:48 PM.
Great to see someone do this. I had been kicking around the idea after seeing how low the CTS gets in price with a bad motor I wouldn't want anyways.
It's got to be one of the easier "swaps" considering you can use GM parts for motor mounts etc.
Ive been wanting to do this conversion ever since everyone said:
it can't be done
just sell it and buy a V
the wiring is gonna be a night mare
its gonna cost too much
well, obviously it can be done
I have less money in this car than I sold my 2004-V and still have the stock engine/trans to sell
and the harness was quite frankly one of the easiest parts of the conversion. Less that 30 wires need terminated into the vehicle to be 100% emissions friendly.
anyway, rant over.
most parts just bolt on but some parts are getting hard to find, even used
other parts just need to be made from scratch because the LS NA engine was never offered in the SIGMA II chassis.
heres some homemade parts
So my tuner was out on Sunday and he removed VATS, DOD/AFM, post O2 and some other junk.
i had some MAF sensor issues but got that figured out. The BCM is communicating with ECM
all instrument gauges are working, transmission TUTD (still on jack stands) tack shows correct
RPM and so on. It's getting real close for a test drive.
I up loaded some videos on YouTube, just search: L76 CTS
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L76/6L80 in SIGMA II 
