LS7 vs. 350 ci LT5 mods

[Paul Workman]

Finally broke down and bought a new HP document scanner to replace the one that died. So, for your viewing pleasure, a comparision of dyno results for the LS7 vs a couple 350 ci LT5s. Interesting...

First the base C6 Z06 w/ LS7:



From a couple years ago, I found this in the archives - Don's car (mods unknown) and Dominic's having the top end ported and ??? (he'll have to say what else). (He has a dyno sheet showing close to 400 RWHP after his last tune before he decided to widen the track by trying to push the guard rails out a little wider with his car (I recon when he gets it running again with the S-II cams and now fully ported, another FBI tire-smoker will be terrorizing the blacktops 'round here!)



And, (as promised) this is my 350 LT5, fully (FBI) ported and tuned. What interesting machines these LT5s are!



I couldn't find any dyno sheets for some 415s, or 427 or 441 LT5s. But, if someone has one/some, and can post them for comparison, that would be cool!

P.

[Demps]

HAT 415, stock valves, LPE B Cams



Ted

[Kb7tif]

Looks like the lowend torque and lowend power are better on the Ls7
I would hope.
Haibeck has dyno charts of maxed out 415's on the site (destroys the LS7).

[USAFPILOT]

Lets see the cost of an LS7 vs anyone's 415. I know 06 Z06's are going for under 40K now on a regular basis. To send my ZR-1 to LPE for a 415 conversion is 29K. I paid 29K for the car a few years ago, so I would have nearly 60K in it. I would be happier with the 415, but the LS7 is looking like a sweet deal these days.

What interests me the most about this is our 350 can get close to the output of the LS7. That is what I am personally shooting for. I want to build the most powerful 350 I can. I should say, one day I will have Corey H do it for me though. I am no engine builder.

[XfireZ51]

Originally Posted by USAFPILOT

Lets see the cost of an LS7 vs anyone's 415. I know 06 Z06's are going for under 40K now on a regular basis. To send my ZR-1 to LPE for a 415 conversion is 29K. I paid 29K for the car a few years ago, so I would have nearly 60K in it. I would be happier with the 415, but the LS7 is looking like a sweet deal these days.

What interests me the most about this is our 350 can get close to the output of the LS7. That is what I am personally shooting for. I want to build the most powerful 350 I can. I should say, one day I will have Corey H do it for me though. I am no engine builder.

Just ask Pete to build you a copy of his motor. I'm looking to have a very respectable street car with similar hp to a C6 Z. Something that can hold its own with the new firepower coming from Dearborn, Warren, and Auburn Hills, Michigan.

[Paul Workman]

Originally Posted by USAFPILOT

Lets see the cost of an LS7 vs anyone's 415. I know 06 Z06's are going for under 40K now on a regular basis. To send my ZR-1 to LPE for a 415 conversion is 29K. I paid 29K for the car a few years ago, so I would have nearly 60K in it. I would be happier with the 415, but the LS7 is looking like a sweet deal these days.

What interests me the most about this is our 350 can get close to the output of the LS7. That is what I am personally shooting for. I want to build the most powerful 350 I can. I should say, one day I will have Corey H do it for me though. I am no engine builder.

Not taking anything away from the C6 Z06 - I'll bet with its weight it would be a hoot to drive. But, back to big motors, I believe FBI'ers - Bob G, Al, and Kevin all built a 427, and two 441 LT5s - all of which would blow an LS7 away across the board. And, the tag was more like $20k - quite a bit less if you did your own porting and disassembly and reassembly.

The nice thing about building a big inch LT5 is much of it can be done in phases - providing some nice performance boosts along the way: porting the top end and timing the cams, and installing headers, for example, could net you a 500 hp 350. All those base pieces would transfer to the big boy (with some further porting and bigger valves, perhaps) so nothing is lost. With the sleeves and portability of parts, the LT5 becomes close to "modular"!

Sorry...My enthusiasm is leaking out again

P.

[FU]

415 12:5 compression

441 11:1 compression

LS7 11:1 compression with headers. Same car with a very small cam 518rwhp 473rwtq

[Kevin]

Originally Posted by Paul Workman

Not taking anything away from the C6 Z06 - I'll bet with its weight it would be a hoot to drive. But, back to big motors, I believe FBI'ers - Bob G, Al, and Kevin all built a 427, and two 441 LT5s - all of which would blow an LS7 away across the board. And, the tag was more like $20k - quite a bit less if you did your own porting and disassembly and reassembly.

The nice thing about building a big inch LT5 is much of it can be done in phases - providing some nice performance boosts along the way: porting the top end and timing the cams, and installing headers, for example, could net you a 500 hp 350. All those base pieces would transfer to the big boy (with some further porting and bigger valves, perhaps) so nothing is lost. With the sleeves and portability of parts, the LT5 becomes close to "modular"!

Sorry...My enthusiasm is leaking out again

P.

I would hope that a heavily modded car will be faster then a stock car. I love the ZR-1 but modding it is becoming cost prohibitive. $10,000 to get mid 400 hp is insane

[XfireZ51]

No doubt in my mind that $4$, the LS7 is hard to beat for mods. You start out at 505hp, headers and a tune and you're looking 550 at the crank. I have a friend with a Silver 07 Z in that configuration. Not to mention it looks like a Great White coming up on your 6 when viewed in the rearview mirror. For a 5.7L, the LT-5 responds incredibly well to even small mods like porting and better exhaust. So the potential is there but the
OHV v OHC differential will always be low end torque which the LS-7 has in spades. Of course, we'll need to see what Todd has cooked up with his 427.

[Paul Workman]

It is becoming obvious that the torque curves on the LT5s are characteristically flatter over all, and especially at the high end. (See how for the most part the LT5s hp is more or less flat going into 7000 rpm, even on stock cams?)

The trouble with "peak" hp and torque numbers is, well, they're "peaky". The greater area under the curve(s) makes more sense when evaluating usable output.

Just food for thought.

P.