Let's talk LS7

[Steve1968LS2]

So.. what's the concensus on using the LS7 block for a build? I've heard some stroke it 4.100" and make a 440, but I'm not sure the sleeves are long enough for that.

What's the max safe bore you can go? I would think that even at the same 427 cui dispalcent there's a ton of potential with the right heads, something like a 235cc AFR or Trick Flow.

I'm thinking I want more displacement for more low and midrange torque. Just exploring ideas right now.

Thoughts?

[Vegas69]

You need help...

[MuscleRodz]

Are you wanting to go to drysump?

[Steve1968LS2]

Are you wanting to go to drysump?

No, don't want to hassle it.. the Canton wetsump deal has been working great for me.

The hassle would be making the LS7 drysump pan clear my rack. I don't need that headache. A wetsump is a direct swap.

[Steve1968LS2]

You need help...

Well grab some wrenches and come on over!!! :idea:

[Damn True]

I kid because I care.

https://static1.pt-content.com/images/pt/2009/08/Psychiatrist-1.jpg

[Vegas69]

LOL...if mine blows, I'm going 540 so don't feel to bad. I know you probably don't want the weight, but what about the LSX block. Can't you get them to almost 500 inches?

[Steve1968LS2]

LOL...if mine blows, I'm going 540 so don't feel to bad. I know you probably don't want the weight, but what about the LSX block. Can't you get them to almost 500 inches?


Weight bad... torque good...

If I put an iron block in my car I might as well go back to leaf springs.. lol

[MuscleRodz]

Why not go LS3? Few changes and it equals the LS7 with out the cost. Also isn't the LS3 block stronger?

[6'9"Witha69]

I call dibs on your takeout!

[Damn True]

I was just thinking the same thing.

[Steve1968LS2]

Why not go LS3? Few changes and it equals the LS7 with out the cost. Also isn't the LS3 block stronger?

Just seems like such a small move in displacement.. from 402 LS2 to at 408 LS3?

The LS3 block is stonger, but since I'm not supercharging or thowing on a big nitrous kit I doubt it matters.

[MuscleRodz]

It is not the displacement, it is the superior head flow.

[Steve1968LS2]

It is not the displacement, it is the superior head flow.

But couldn't you put LS3 heads on an LS7 and have both? :)

[Rybar]

Steve, if you want more torque why not put a blower on your current motor and drop the compression? Could probably save you a bundle of $$$.

[Steve1968LS2]

Steve, if you want more torque why not put a blower on your current motor and drop the compression? Could probably save you a bundle of $$$.

Part of me want's a blower.. but for the most part I like the NA route.. far more reliable and "simplistic" which has always been my goal with this car.

I suppose I could get an LS3 and stroke it..

Hey, here's a question.. what if my I put my LS2 stroker assembely into the LS3? hmmm.. Too bad the bore is bigger (4.06 compared to 4.005).. the crank and rods should work though.

I just like to consider this stuff.. I never really consider my car "done".. what fun is there in that?

[Smitty_67]

I thought you were looking at an LSA?

http://cgi.ebay.com/ebaymotors/2009-Cadillac-CTS-V-6-2L-Supercharged-LSA-V-8-Liftout_W0QQitemZ370241464971QQcmdZViewItemQQptZMo tors_Car_Truck_Parts_Accessories?hash=item56341c6a 8b&_trksid=p4506.c0.m245

[Camaross82]

If only I had that decision to stress over.

[Steve1968LS2]

I thought you were looking at an LSA?

http://cgi.ebay.com/ebaymotors/2009-Cadillac-CTS-V-6-2L-Supercharged-LSA-V-8-Liftout_W0QQitemZ370241464971QQcmdZViewItemQQptZMo tors_Car_Truck_Parts_Accessories?hash=item56341c6a 8b&_trksid=p4506.c0.m245

I was researching since we are putting one in the Project American Heroes Chevelle...

I was tempted a bit on mine but then common sense took over.

[Smitty_67]

I was researching since we are putting one in the Project American Heroes Chevelle...

I was tempted a bit on mine but then common sense took over.

Did you see the combo on ebay? Looks like a good deal.

[WS6]

You'd be better off stroking an LS3. It will save a couple thousands not having to buy the LS7 block. Sure you'll have 10 cubic inches less but you'll have enough trouble putting all the torque down regardless. The LS7 heads are better but are very expensive again. LS3/L92 would be great or the AFR large runner heads. Didn't they just come out with a 240cc runner head also? I love the C6 Z06 and wouldn't change anything on the engine if I owned one. If I building something though, I prefer inexpensive and good. The LS7 is not inexpensive. You can build more for less.

[Kenova]

If you don't want to use the dry sump system or forced induction, Katech sells a sleeved LS2 block (4.125"). I'm not sure of the price difference though. If it costs less then you have more $$$$$ for other "stuff".

Ken

[The WidowMaker]

i looked into sleeving a ls3 block or running a stock ls7 block. the ls3 block was going to be more than the ls7 and both were more expensive than the lsx block.

anyone running the texas speed ls7 heads? amazing price, huge claims, and both good and bad reviews. for the price, i dont know if they can be beat.........

also, since im only a few miles away from you, you won't have to crate and ship the old motor. it would go reeeeeeeeal nice btwn the velles fenders.

Tim

[Steve1968LS2]

You'd be better off stroking an LS3. It will save a couple thousands not having to buy the LS7 block. Sure you'll have 10 cubic inches less but you'll have enough trouble putting all the torque down regardless. The LS7 heads are better but are very expensive again. LS3/L92 would be great or the AFR large runner heads. Didn't they just come out with a 240cc runner head also? I love the C6 Z06 and wouldn't change anything on the engine if I owned one. If I building something though, I prefer inexpensive and good. The LS7 is not inexpensive. You can build more for less.

I think you're right.. Any reason I couldn't take the Lunati crank and rods from my 402 and put them in the LS3? I know I would need new pistons.

The the LS3 crank and rods could go in the LS2 with the current forged pistons (as a spare engine)..

I guess I need to do the math.. lol

[WS6]

I think the crank and rods will fit fine. Since they are both Gen 4 motors, the reluctor rings are the same too. I'd double check with Lunati to be certain but nothing is coming to mind right now that says no, they won't swap.

[Steve1968LS2]

I think the crank and rods will fit fine. Since they are both Gen 4 motors, the reluctor rings are the same too. I'd double check with Lunati to be certain but nothing is coming to mind right now that says no, they won't swap.

I don't see a problem either.. hey, what length are stock LS2/LS3 rods?

[68sixspeed]

Steve- LS7 stuff- check with Jason over at Katech-- they are pricey but know these motors and improvements to them better than anyone. I have one ready for my 68 convertible (that should make it twist!), before it goes in it's getting the Katech oil pump, different rockers (07's had some needle bearing issues for a few months), and a bigger tank. Given the track use of your car it would be nice to keep the dry sump, maybe an ARE or other aftermarket pan can clear your rack? -Dan

[WS6]

6.1" according to this website. It's just below the picture of the connecting rod a ways down. This article is full of good info about the design of the engines.

http://www.camarohomepage.com/ls3/

[Mike Norris]

Though they can be a bear to control on a road course, I would say if low end is what you are looking for then a TVS2300 with 5-6 PSI on what you have would be more then enough. Simple to do as it is just a bolt on and tuning without changing anything in the engine, should fit under the current hood and probably make 550-600 RWT at 2500-3000 RPM.

Let me know if you need someone to do the project for ya :cheers: Time for a little east coast press.

Mike Norris

[Steve1968LS2]

Though they can be a bear to control on a road course, I would say if low end is what you are looking for then a TVS2300 with 5-6 PSI on what you have would be more then enough. Simple to do as it is just a bolt on and tuning without changing anything in the engine, should fit under the current hood and probably make 550-600 RWT at 2500-3000 RPM.

Let me know if you need someone to do the project for ya :cheers: Time for a little east coast press.

Mike Norris

I need you to take a vacation in SoCal sometime in late October.. planning on going to SEMA?

Here's the deal.. GMPP is shipping me an LS3 crate engine on Monday to do a series of stories on. If I have it I might as well use it. I like the TVS deal, just not sure it's the right way to go for autocross and such.

[Mike Norris]

I will be heading to SEMA for sure and a trip to SoCal ahead of time is not out of the question. I just need to know what you need.

I do agree with the SC and autocross not mixing well in most cases and that is why I figured on a low boost deal. But the LS3 setup will work. A stroker 418 with a proper set of CNC ported LS3 heads and cam will make a bunch of good low end, peak a bit early, but still pull to a decent RPM.

Let me know and talk to you soon.

Mike Norris

[TT302Z28]

OK...just my $.02...Have you thought about turbos? We put turbos on a basic LS1 with an LS6 cam and mild ported heads. This is in a Chevelle located in Roseville, CA. It dyno'd at 523 RWHP. When you are off the peddle it runs like a stocker, floor it and hang on.

Steve, if you are in N.CA I can get you a ride. With your current engine turbos would be a great way to go. Just run lower boost to avoid over pressuring your cylinders.

[Mike Norris]

"Have you thought about turbos?'

I like a great TT setup any day, and just take a look at what we did with Motiv8r for Larry Callahan. But they have the same inherent issues on a road course or autcross. As with a TVS2300, the boost comes on so quick and hard it can be a bear coming out of corners on the DOT tires some races require.

Now, you could run an electronic boost controller by RPM :idea:

Mike Norris

[Bowtie racing]

I will be heading to SEMA for sure and a trip to SoCal ahead of time is not out of the question. I just need to know what you need.

I do agree with the SC and autocross not mixing well in most cases and that is why I figured on a low boost deal. But the LS3 setup will work. A stroker 418 with a proper set of CNC ported LS3 heads and cam will make a bunch of good low end, peak a bit early, but still pull to a decent RPM.

Let me know and talk to you soon.

Mike Norris


Sorry to mix in this...

Mike i have been thinking this same set up . LS3+TVS2300.

What kind of power do you think there is available with combination you suggest above? Can the TVS cooler handle the IAT temps in long term driving ?

[Mike Norris]

With an 8 or 10 rib drive I think getting to the 700-750 RWHP area is feasible. IAT's with a proper heat exchanger should be in the 120* range for daily driving & playing and if driven hard in the 160-170* area. These are just gueses as I have not a big boost TVS yet, but I would imagine it to be close. Proper tuning will be the key to long term durability.

Hope this helps.

Mike Norris