deaker11

Found a pretty good deal on an LS7 recently and looking forward to building up an awesome beast, and doing as much of the work myself as possible.

My question(s), and the point of my post is to get feedback from those who have done this before.

Any tips, tricks, potential gotchas, etc. that could be imparted would be greatly appreciated.

Examples might be something like:

Will I need to replace the wiring harness and PCM or will the stock LS3 components work just fine. My local tuner uses EFI Live, so I would assume they have full control of most of the typical variables, but one never knows for sure until it's been done.

Another - I will probably upgrade the stock clutch anyway, but what about the bell housing. Again, I would assume it would mate up to the LS7 as easy as the LS3, but just not 100% certain.

I'm sure there are dozens of other minor(or not so minor) things, and I'd be interested to hear about anything that might save me time or from making mistakes.


Just as background...
Since I purchased in Nov. 08, I've already done the typical bolt-ons (Kooks LT headers + x-pipe, and vararam CAI), plus cam, and of course a good tune. I'm a little disappointed and would have expected to be closer to ~470rwhp on the dyno, but only reached 434rwhp. I realize how the dyno stuff goes, and the seat of the pants test is a noticeable increase, but it's not really that significant. I'm figuring the LS7 with the best components I can afford should put me well over 500rwhp N/A, as well as put me in a good position for FI later down the road after upgrading brakes, suspension, wheels, etc.

ramrodw30

just buy a Z06, don't waste your time on this.

LS1LT1

Or better yet, just modify the LS3 (heads and cam, gears etc.). In some ways the LS3 might be a better motor to modify than the LS7, especially if going forced induction or nitrous.
I feel that it's just too new of a car to do a full motor swap like that, maybe if I had a high mileage 2005 I would consider it.
If serious about it though try and contact Christopher (screen name: 'thesubfloor'), he did the swap on his LS2 car and also on a friend's car as well I believe.

thesubfloor

Send me a PM with your phone number and I'll give you a call about it.

Christopher

carlrx7

um 434 ??/ WAYYY LOW!!

there are guys over 510 RWHP cam only LS3's!! get a differnt cam..

ls3 already uses the ls7 clutch.

again.. not worth the trouble, but get a differnt came, and youll be smokin bolt on z's

CPG1962

I agree with all others - its not worth it. Simply add a cam, SC, turbo, gearing or a mix to your LS3.

FloydSummerOf68

WTF cam did you add to only pull 434rwhp? What kind of dyno was that on?

The cost of the motor + new wheels/tires to hold the power + the going price of your car would probably put you very near a low mileage Z06.

Dont waste your time with the swap.

I would personally rather mod the LS3 over the LS7, but I would take a Z06 over a modded LS3.

da vette guy

don't know if it is worth it or not but i would like to know what is involved to make the swap.......... if it bolts in without a lot of hassle i'd go for it....

deaker11

Thanks much for all the feedback. I can appreciate the logic. I had already planned on talking to my tuner about a different cam before I ran across the LS7. I had seen a lot of evidence that 434 is pretty low with the current mods.

On one hand I was/am very excited about building up a streetable 427 putting down 500+rwhp, as well as turning a wrench on the vette. On the other hand, I've really been bitten before by practically unsolvable computer and electronics issues working on late model vehicles, but I've never owned a vette before(always wanted one). If it's just a matter of getting all the right parts and/or moving stuff around a bit, then I'm all about it as long as it all doesn't cost a fortune. However, if I end up fighting a losing battle with the computer then I would just sell the LS7 and spend the money on more upgrades for the existing LS3.

I'm out town until Monday, but I plan to speak with Christopher before making a final decision.

Everyone's feedback is much appreciated!

FloydSummerOf68

A head/cam combo with decent parts makes 500 streetable rwhp in an LS3.

JayplaySS2

Don't bother. A good H/C LS3 should make 500-520rwhp. Add rockers and a ported FAST 102 and you could see 540-550rwhp when it's all said and done with a big cam. Not to mention LS3's are much cheaper to fix if you ever destroy a shortblock.

An LS7 factory option in a base/Z51 coupe would be cool as hell though as I said before in a different thread.

Silver Bullet C6

If you are just looking to have a very fast street car, supercharge it and be done. I tried going N/A first and after I went S/C the difference was HUGE. S/C is your best "bang for the buck" IMHO.

NIGHTSTALKER

Like others have said....Stick with the LS3. Look at my sig. Look at what my tuner was able to come up with on my LS2. I smoke bolt-on Z's with my little POS LS2 ....To me, that is making a better statement to the the other guy than saying..."Yeah, it's got an LS7".....Don't get me wrong, having an LS7 in a Standard C6 would be nice, and not too many guys have done it, but I think it's not worth the hasstle. Build your LS3!
Good Luck.

Black02SS

I'll disagree with the above statements. Go for it. Convert the LS7 to a wet sump and it will be a drop in deal. The extra power you gain from the LS7 due to the added cubic inches will be worth it. Also like everyone has said, not many have a LS7 in a stock C6 coupe.

JayplaySS2

An LS7 swap is only going to net you about 40-55rwhp if it's stock. Very easy to surpass that with a cam and tune on the LS3. Is a cam cheaper than an LS7 swap?

Good luck either way and if you do it, post lots of pics.

Wallacefl

driven or been in many modded LS3s and IMHO any really "cammed"ie: intake duration > 215 and/or LSA <116 in a LS3 will never have the low speed manners of a stock LS7 with it's LSA 0f 120.

deaker11

This is the other side of the coin that I wanted to hear folks chime in on as well.

I know I can go crazy modding the LS3 and achieve outrageous power, but what about street manners. I'm definitely not an expert with this platform, but I do know the universal rule of thumb that more cubes usually yields more power with less effort.

If I go with the LS7 I would definitely not go 100% stock. At least a mild to moderate cam, but I would also want to strike a balance as a daily driver, as well as take to the track occasionally.

The supercharger comments make a lot of sense too. I've heard from a lot of folks that the LS3 really likes the boost. I've done the supercharger thing before and blew a motor. I can probably get over that, but right now I'm just looking forward to the fun and experience of the DIY work. Unless it's just really likely to turn out to be a disaster, which is why I did this post. I'm looking forward to speaking with Christopher since he's done it a few times.

EuroRod

Sell the LS7, and slap a blower on that puppy.

Ragtop 99

Go drive a stock Z06 and see how it feels. A big cam 500 rwhp LS3 will not feel the same as a small cam 530 rwhp LS7 because of the midrange torque difference.

Have you considered stroking your current motor? A 4" crank and a little clean up of the LS3 heads would give you the big midrange, easy street manners, and put you above 500 rwhp.

ctsv510

superchargers are the replacement for displacement.