mikesanto70

Has anyone swapped a 2006-2009 LS4 5.3 V8 from a FWD Monte SS into a FWD Cadillac DTS of FWD Seville STS or SLS . They are nice cars except that Northstar has issues with overheating and being an overall unreliable POS compared to a nice LS motor that would run nice in one of those, Imagine doing a heads and cam LS4 5.3 in a nice caddy, that would be a nice DD (daily driver) and even stock would be nice, but if you did a cam swap and maybe some nice heads, that thing would rip!!! FWD burnouts for miles !!! lol... Anyway, what would be needed to accomplish this, would that LS4 motor and trans bolt right in or would there be a wheelbase issue to deal with, any insight on this would be appreciated!! Thanks in advance !!

Mike Santo
Scottsdale, Arizona USA

fieroguru

iTrader: (1)

The 4T80 with the N* will not clear the block of the LS4, so you would have to swap over the LS4's 4T65e-hd as well (it also saves you from starter mount head aches) and you should get it (the transmission) rebuilt before doing the swap.

The rest of it will be mounts, axles, and harness interface to the caddy.

mikesanto70

Yeah I planned on using the LS4 trans too, but will it drop right in? Do I need the CV's from the Monte and the motor and tranny mounts from the Monte and then as far as the electronics, would The ECM from the donor car need to be piggy backed or put in place of old computer or could I tune the caddy ECM for the LS4? Also, are the LS4 fwd trannys weak, is that why you suggested a rebuild or is it just smart to do because of being a pain in the *** to remove when it grenades!!!
Thanks,

mikesanto70

I'm a wholesaler and I come across the caddys all the time and they are nice clean cars and cheap but that NS engine is a shitbox and I was going to buy another Crown Vic or town car because some idiot chick texting totaled my mint DD C Vic, I was going to do a turbo 6.0 swap in the Vic before it got totaled because believe it or not that car handled like a mo fo for such a big heavy beast, now i know why cops used them..lol.. but these caddys are super plush and ride awesome but I dont want a headache car, especially out here in the summer because it gets 118 degrees and being stranded/brokedown in that **** sucks big time!!!

mikesanto70

Wow no other replies, not avery hot subject, I guess if its not a 1st gen camaro or a pickup, nobody even gives a care to look, oh well, I'll figure it out on my own!!!!

fieroguru

iTrader: (1)

The LS4/4T65e-HD has been swapped into Fieros several times, but what you are asking about would be the first swap of its kind, so there is no published information about what all parts you need to make it work.

You will need to figure out the mounts, axles (can stock GM axles be used to assemble the needed axles, or will you have to go custom), and ECM/TCM integration into the chassis and what it takes to keep everything working in the dash. Its just one of those swaps you have to figure out if you want to do it.

As for rebuilding the 4T65e-hd, they fail in their stock platform. Ask it to haul around a heavier chassis will just make it happen faster.

lightning95sc

I'm interested in this swap, too.

I've been thinking about this swap for a while as DTS's and STS's are dirt cheap in my neck of the woods.

My buddy has a salvage yard and he has some wrecked and stripped Impala SS's. I may get a subframe and see how similar it is to the Cadi.

Chuck

tonypaul

iTrader: (2)

Fieroguru pretty much gave you the best advice thats going to be out there. He is a master at these LS4 swaps as well as a great over all fabricator. If anyones going to have real advice its going to be him. Its going to be on of those swaps where your going to have to figure it out as you go. The wiring is going to be one of the biggest hurdles.

In my opinion- even if you got a super great deal on a Caddy, and a decent deal on LS4 drivetrain the cost of the over swap would be greater than the car would be worth. I swapped a LS4 into a Lambo Diablo kit car on a modded Fiero chassis and I can tell you its all the little stuff that adds up quick.

Although with a little amount of tweeking the LS4 can put out some decent power but the transmission is the weak link. It can be upgraded but again more money. In the end, if you get it finished and running/functioning its not going to have anymore more power than the Northstar would. ie- Nothing overly exciting to drive...

If you have alot of time, a strong skill set for fabrication and wiring as well as good chunk of cash - go for it.... but again- In my opinion- all that time and money would go a long way in building something thats going to be fun to drive and have some kind of resell value.

pdsq98gt

The cradles are different in where the mount bolts are. I would use the caddy cradle with some homemade mounts to mount the ls4/4t65e. I would also use the ls4 harness and ECM/TCM. I think you will definitely have to have custom axles (unless you get really lucky). Really shouldn't be that difficult of a swap though.

John Lee

I don't see why it wouldn't work. Cv axles from cts-v should work I believe.

John Lee

I'm gonna try it out. I know a guy with the I can make it work attitude. When we are done I'll send you the video.

AAIIIC

iTrader: (19)

Which CTS-V? Regardless of which generation of V you're looking at, I'm gonna go out on a limb and guess that the CTS-V's inner and outer CVs share no commonality with the inner and outer CVs on an LS4/4T65e-hd car, not to mention the length of FWD and RWD axles are typically not the same. But other than those minor details, I'm sure CTS-V axles should work great!

Don't keep us hanging that long, update this thread with some build photos when you get the project going! I think you've got a rough road ahead, but it could be cool if you're able to pull it together.

Todd Hazel

Did the conversion of an LS engine I to a Cadillac DTS ever get completed? Any updates? I'm interested in doing this as well. Looking for anyone out there with a success story. I also would like to convert it to bed as some of the other bloggers here we're discussing.

Todd Hazel

Auto correct stries again... I am also interested in converting my DTS to rwd as some of the bloggers here we're discussing. Any advice or success stories are welcome.