Modifying an LT4 vs. LS1
Thread Starter
Burning Brakes
Joined: Mar 2002
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From: Camarillo California
Modifying an LT4 vs. LS1
Hi Guys. I've been thinking about buying a '96 Grand Sport and if I do, there's no way the motor would stay stock. Being an old-school guy, I'm not too familiar with the LT4, but I've been advised to stick with a C5 because the LS1 is a far better platform on which to build. Can anybody tell me what the advantages of the LS1 over the LT4 are?
I talked with LPE and they say the positioning of the factory cats on the LT4 make it difficult (if not impossible) to do a long-tube header setup and stay legal, whereas the LS1 at least has the cats further downsteam. I imagine the LS1 heads probably have more potential too, although can't the LT4 heads be made to flow pretty well? Is the LS1 really "that much" better?
I talked with LPE and they say the positioning of the factory cats on the LT4 make it difficult (if not impossible) to do a long-tube header setup and stay legal, whereas the LS1 at least has the cats further downsteam. I imagine the LS1 heads probably have more potential too, although can't the LT4 heads be made to flow pretty well? Is the LS1 really "that much" better?
Team Owner
Joined: Apr 2001
Posts: 36,453
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From: Overwhelmed as one would be, placed in my position.... DFW, TX
St. Jude Donor '05
I own both (well, mine's an LT1, but the situaiton is very similar).
The LS1 will make stupid power with just a cam and bolt ons(450 rwhp on a G5X3 is not unheard of). For that on an LT4, you're gonna need a LOT more work- H/C for sure, maybe a stroker. The simple fact is that the LS1 is a better motor and the C5 is a better chassis. If a modded street rod is your desire and you have the cash, go for the C5. IMHO, this is not even debatable- it's simply fact.
The C5 is better ergonomically, has a better suspension setup (true dual A-arms front AND rear), has a much stiffer chassis, has a much more mod-friendly motor, and has a TON more aftermarket support at the moment. Some people (especially on this forum) will disagree with me, but I think they're biased towards the C4 for other reasons.
The LS1 will make stupid power with just a cam and bolt ons(450 rwhp on a G5X3 is not unheard of). For that on an LT4, you're gonna need a LOT more work- H/C for sure, maybe a stroker. The simple fact is that the LS1 is a better motor and the C5 is a better chassis. If a modded street rod is your desire and you have the cash, go for the C5. IMHO, this is not even debatable- it's simply fact.
The C5 is better ergonomically, has a better suspension setup (true dual A-arms front AND rear), has a much stiffer chassis, has a much more mod-friendly motor, and has a TON more aftermarket support at the moment. Some people (especially on this forum) will disagree with me, but I think they're biased towards the C4 for other reasons.
Le Mans Master
Joined: Jul 2000
Posts: 5,012
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From: OKC OK
Originally Posted by Umrswimr
I own both (well, mine's an LT1, but the situaiton is very similar).
The LS1 will make stupid power with just a cam and bolt ons(450 rwhp on a G5X3 is not unheard of). For that on an LT4, you're gonna need a LOT more work- H/C for sure, maybe a stroker. The simple fact is that the LS1 is a better motor and the C5 is a better chassis. If a modded street rod is your desire and you have the cash, go for the C5. IMHO, this is not even debatable- it's simply fact.
The C5 is better ergonomically, has a better suspension setup (true dual A-arms front AND rear), has a much stiffer chassis, has a much more mod-friendly motor, and has a TON more aftermarket support at the moment. Some people (especially on this forum) will disagree with me, but I think they're biased towards the C4 for other reasons.
The LS1 will make stupid power with just a cam and bolt ons(450 rwhp on a G5X3 is not unheard of). For that on an LT4, you're gonna need a LOT more work- H/C for sure, maybe a stroker. The simple fact is that the LS1 is a better motor and the C5 is a better chassis. If a modded street rod is your desire and you have the cash, go for the C5. IMHO, this is not even debatable- it's simply fact.
The C5 is better ergonomically, has a better suspension setup (true dual A-arms front AND rear), has a much stiffer chassis, has a much more mod-friendly motor, and has a TON more aftermarket support at the moment. Some people (especially on this forum) will disagree with me, but I think they're biased towards the C4 for other reasons.
Stock to stock they run very similar...when modded the LSx motors kick the **** outta the LTx motors/cars...period. I still think the C4 cars look much better than the C5 cars.
Melting Slicks
Joined: May 2002
Posts: 2,670
Likes: 4
From: Severna Park MD
Originally Posted by AmericanPie
Hi Guys. I've been thinking about buying a '96 Grand Sport and if I do, there's no way the motor would stay stock. Being an old-school guy, I'm not too familiar with the LT4, but I've been advised to stick with a C5 because the LS1 is a far better platform on which to build. Can anybody tell me what the advantages of the LS1 over the LT4 are?
I talked with LPE and they say the positioning of the factory cats on the LT4 make it difficult (if not impossible) to do a long-tube header setup and stay legal, whereas the LS1 at least has the cats further downsteam. I imagine the LS1 heads probably have more potential too, although can't the LT4 heads be made to flow pretty well? Is the LS1 really "that much" better?
I talked with LPE and they say the positioning of the factory cats on the LT4 make it difficult (if not impossible) to do a long-tube header setup and stay legal, whereas the LS1 at least has the cats further downsteam. I imagine the LS1 heads probably have more potential too, although can't the LT4 heads be made to flow pretty well? Is the LS1 really "that much" better?
Of course if you are talking LS1 then you aren't talking a legal Grand Sport in Kali are you?
Anywhere else in this great nation you can build a really strong LT4. Looks like you are stuck with a C5. The smog ***** say "No Grand Sport for you!"
Last edited by FELNGR8; Apr 4, 2006 at 02:39 PM.
Melting Slicks
Joined: Mar 2003
Posts: 2,472
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From: Toronto ONTARIO
IMO the ls1 engine overall is just a better design. its a modern researched and develpoed engine. better airflow ( not just peak cfm but at low lift the ls1 is superior ), better combustion design, better manifold design (arguably). It ShOULD a much better design because it was ground up. and it is. 6 bolt mains.. deep skirt etc etc. there are downsides like it having an aluminum block (max power wise with superchargers or turbos although it is much lighter than iron) and... well i cant think of many more atm 
Now that ive said that i think many of the numbers are inflated for the ls1 modified cars. many tuners who 'emerged' when the c5 came out know how to play with their dynoes to produce astronomical #s. what do i mean? explain how a stock lt1 and ls1 both make 345-350 hp. but one with heads and cam can get 250 MORE rwhp than stock.. and the other.. 100 ?
I dont buy it. I have a few friends i street race with c5s who have modified engines from ARE and Carket etc and although the hp #s can sound super duper high the torque #s are nowhere near. What I mean is that this 475 rwhp car my friend has doesnt run superfast #s or the times you would expect.
Hp sells.
Now that ive said that i think many of the numbers are inflated for the ls1 modified cars. many tuners who 'emerged' when the c5 came out know how to play with their dynoes to produce astronomical #s. what do i mean? explain how a stock lt1 and ls1 both make 345-350 hp. but one with heads and cam can get 250 MORE rwhp than stock.. and the other.. 100 ?
I dont buy it. I have a few friends i street race with c5s who have modified engines from ARE and Carket etc and although the hp #s can sound super duper high the torque #s are nowhere near. What I mean is that this 475 rwhp car my friend has doesnt run superfast #s or the times you would expect.
Hp sells.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
Originally Posted by Umrswimr
I own both (well, mine's an LT1, but the situaiton is very similar).
The LS1 will make stupid power with just a cam and bolt ons(450 rwhp on a G5X3 is not unheard of). For that on an LT4, you're gonna need a LOT more work- H/C for sure, maybe a stroker. The simple fact is that the LS1 is a better motor and the C5 is a better chassis. If a modded street rod is your desire and you have the cash, go for the C5. IMHO, this is not even debatable- it's simply fact.
The C5 is better ergonomically, has a better suspension setup (true dual A-arms front AND rear), has a much stiffer chassis, has a much more mod-friendly motor, and has a TON more aftermarket support at the moment. Some people (especially on this forum) will disagree with me, but I think they're biased towards the C4 for other reasons.
The LS1 will make stupid power with just a cam and bolt ons(450 rwhp on a G5X3 is not unheard of). For that on an LT4, you're gonna need a LOT more work- H/C for sure, maybe a stroker. The simple fact is that the LS1 is a better motor and the C5 is a better chassis. If a modded street rod is your desire and you have the cash, go for the C5. IMHO, this is not even debatable- it's simply fact.
The C5 is better ergonomically, has a better suspension setup (true dual A-arms front AND rear), has a much stiffer chassis, has a much more mod-friendly motor, and has a TON more aftermarket support at the moment. Some people (especially on this forum) will disagree with me, but I think they're biased towards the C4 for other reasons.
However, the C5 styling has never done anything for me -- just my personal opinion, nothing more.
I own an original (all stock) C2 and a modified '92 C4.
I have no desire for any others.
Tom Piper
Le Mans Master
Joined: Feb 1999
Posts: 9,916
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
You can make stupid power( read "uneusable") with a supercharger on a LTx motor, even without LT's. The may have bullet cats from Random? Nt as much as a LSx motor.
And like Tom Said, the C5 just doesnt look right, no matter how well built it is. Front end is kinda cheap looking, and the back is HUGE.
My C4 makes 425rwhp and is NOT emissions legal, Sorry Bogus
But when I go back to SC, it wont matter, no laws so far.
And like Tom Said, the C5 just doesnt look right, no matter how well built it is. Front end is kinda cheap looking, and the back is HUGE.
My C4 makes 425rwhp and is NOT emissions legal, Sorry Bogus
But when I go back to SC, it wont matter, no laws so far.
Thread Starter
Burning Brakes
Joined: Mar 2002
Posts: 960
Likes: 12
From: Camarillo California
Originally Posted by FELNGR8
Lingenfelter as a major business can't get away with replacing the stock cats (with aftermarket) on mod packages they do. If in California you can't touch the cats then forget about modding an LT4. You will need long tube headers to get the HP you expect even from a stroker. Callaway does port the stock iron exhaust manifolds on Supernatural cars which leaves them Kali smog legal. So that's an option for a modded GS.
Of course if you are talking LS1 then you aren't talking a legal Grand Sport in Kali are you?
Anywhere else in this great nation you can build a really strong LT4. Looks like you are stuck with a C5. The smog ***** say "No Grand Sport for you!"
Of course if you are talking LS1 then you aren't talking a legal Grand Sport in Kali are you?
Anywhere else in this great nation you can build a really strong LT4. Looks like you are stuck with a C5. The smog ***** say "No Grand Sport for you!"
I was amazed to see the numbers the LSx motors are generating with just a few mods. My brother has a '99 FRC and went with an LPE head/ cam package; it now puts out 427 rwhp. Yet LPE's 383 stroker package for the LT4 is rated at only 450 fwhp...i.e., less than 400rwhp. Part of the problem is, they can't legally install headers on the LT4.
Personally, I like the looks of both the C5 and the C4. But if the C5 really offers that much more performance potential, well, I'll probably head in that direction.
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Team Owner
Joined: Apr 2001
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From: Overwhelmed as one would be, placed in my position.... DFW, TX
St. Jude Donor '05
Originally Posted by steve40th
You can make stupid power( read "uneusable") with a supercharger on a LTx motor, even without LT's. The may have bullet cats from Random? Nt as much as a LSx motor.
And like Tom Said, the C5 just doesnt look right, no matter how well built it is. Front end is kinda cheap looking, and the back is HUGE.
My C4 makes 425rwhp and is NOT emissions legal, Sorry Bogus
But when I go back to SC, it wont matter, no laws so far.
And like Tom Said, the C5 just doesnt look right, no matter how well built it is. Front end is kinda cheap looking, and the back is HUGE.
My C4 makes 425rwhp and is NOT emissions legal, Sorry Bogus
But when I go back to SC, it wont matter, no laws so far.
Or buy a big cam and a set of LT's for the C5 and you'll have 450 rwhp. Cost- maybe $3k if you splurge.
Last edited by Umrswimr; Apr 4, 2006 at 03:24 PM.
Melting Slicks
Joined: Mar 2003
Posts: 2,472
Likes: 0
From: Toronto ONTARIO
427 rwhp is not unheard of in c4 land. there are many f-bodies and ltx cars with a real decent cent of worked heads that can hit 400+ rwhp. An LT4 is rated at 300 rwhp or so. With a nicely worked set of heads and a cam alone i dont see how 100 rwhp is impossible.
What it all comes down to is how much $$ do you have to spend. $$$$ buys speed
What it all comes down to is how much $$ do you have to spend. $$$$ buys speed
Last edited by DieL; Apr 4, 2006 at 03:29 PM.
Burning Brakes
Joined: Sep 2005
Posts: 993
Likes: 3
From: Iowa
Just go with the car that you like. HP is there for anyone in any car in one form or another. As for the LS to LT platform I don't have a preference. Both work well for a hot street set up; I would have to say that I like the driveline in the c4 better so that would be my choice.
Le Mans Master
Joined: Feb 1999
Posts: 9,916
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Originally Posted by Umrswimr
Sure. Bolt on a supercharger for a mere $6k and you'll have 450 rwhp if you're lucky through stock manifolds.
Or buy a big cam and a set of LT's for the C5 and you'll have 450 rwhp. Cost- maybe $3k if you splurge.
Or buy a big cam and a set of LT's for the C5 and you'll have 450 rwhp. Cost- maybe $3k if you splurge.
Yes the LSx are cheaper to modify, but C5 just isnt all that appealing to some. Its just an opinion.
Le Mans Master
Joined: Feb 1999
Posts: 9,916
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Originally Posted by AmericanPie
...which is one more reason why so many of us (working taxpayers, at least) are leaving the state. Maybe I'll be next.
I was amazed to see the numbers the LSx motors are generating with just a few mods. My brother has a '99 FRC and went with an LPE head/ cam package; it now puts out 427 rwhp. Yet LPE's 383 stroker package for the LT4 is rated at only 450 fwhp...i.e., less than 400rwhp. Part of the problem is, they can't legally install headers on the LT4.
Personally, I like the looks of both the C5 and the C4. But if the C5 really offers that much more performance potential, well, I'll probably head in that direction.
I was amazed to see the numbers the LSx motors are generating with just a few mods. My brother has a '99 FRC and went with an LPE head/ cam package; it now puts out 427 rwhp. Yet LPE's 383 stroker package for the LT4 is rated at only 450 fwhp...i.e., less than 400rwhp. Part of the problem is, they can't legally install headers on the LT4.
Personally, I like the looks of both the C5 and the C4. But if the C5 really offers that much more performance potential, well, I'll probably head in that direction.
Instructor
Joined: Feb 2000
Posts: 195
Likes: 0
From: Woodbridge VA
One item I think that has been missed is, the Grand Sport is or will be a collector's item, because it was only build for one year and its the only one that came stock with a LT4 (I know all '96 six speeds have the LT4). C5s are a dime a dozen.
zzzasy
'96 LT4
zzzasy
'96 LT4
Melting Slicks
Joined: May 2002
Posts: 2,670
Likes: 4
From: Severna Park MD
One thing that isn't clear here. Are you talking a 96 6 speed car with the throttle body plate that says "Grand Sport", or you talking one of 1000 skunk white stripe over blue real Grand Sport?
Because it seems to me if you wanted a real Grand Sport you wouldn't be asking how much HP you can make with mods.
If you are talking 96 6 speed car with the LT4 motor, then get a C5 instead and be one of many thousands owners with fast but but ugly boring cars. JMO.
Because it seems to me if you wanted a real Grand Sport you wouldn't be asking how much HP you can make with mods.
If you are talking 96 6 speed car with the LT4 motor, then get a C5 instead and be one of many thousands owners with fast but but ugly boring cars. JMO.
Race Director
Joined: Dec 2002
Posts: 13,348
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Originally Posted by FELNGR8
One thing that isn't clear here. Are you talking a 96 6 speed car with the throttle body plate that says "Grand Sport", or you talking one of 1000 skunk white stripe over blue real Grand Sport?
Because it seems to me if you wanted a real Grand Sport you wouldn't be asking how much HP you can make with mods.
Because it seems to me if you wanted a real Grand Sport you wouldn't be asking how much HP you can make with mods.
To me, the big reason for starting with the LS1 would be the number of tuners who will work on them. Try to find a local tuner who gets excited about a C4......
...or even has much experience with them.Larry
code5coupe
Pro
Joined: Feb 2005
Posts: 632
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From: Harrisburg, PA 86 Vert w/ 89 wheels
another vote for keeping the grand sports original.
You'll pay way more for a good condition GS than you would for a regular 6 speed LT4.
Then to modify it and depreciate the car, it'd be hard to sell later. I love Grand Sports and if I'm ever ready to get mine, no way in heck I'd buy a modified one.
Just my opinion.
Then the LS1's do seem to be better platforms to build upon.
Seems like a no brainer to be honest.
You'll pay way more for a good condition GS than you would for a regular 6 speed LT4.
Then to modify it and depreciate the car, it'd be hard to sell later. I love Grand Sports and if I'm ever ready to get mine, no way in heck I'd buy a modified one.
Just my opinion.
Then the LS1's do seem to be better platforms to build upon.
Seems like a no brainer to be honest.
Thread Starter
Burning Brakes
Joined: Mar 2002
Posts: 960
Likes: 12
From: Camarillo California
Originally Posted by ZZZASY
One item I think that has been missed is, the Grand Sport is or will be a collector's item, because it was only build for one year and its the only one that came stock with a LT4 (I know all '96 six speeds have the LT4). C5s are a dime a dozen.
zzzasy
'96 LT4
zzzasy
'96 LT4
) but the overall package has really grown on me lately. There are a couple of mint, low-mileage ones on Ebay right now that are garnering bids around $30K. It seems like a pretty good buy for a limited edition Corvette that's barely broken in. As far as modifying one, what would be wrong with that as long as the car appears externally stock and retains matching numbers? A cam, some headwork, possibly long tubes...maybe even a stroker. Especially if done by a reputable tuner like LPE. It would only increase the fun factor and result in a more desireable Vette IMO. Absolutely no Frankenstein bodywork or tack-ons though.
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St. Jude Donor '09 thru '20
Originally Posted by Umrswimr
I own both (well, mine's an LT1, but the situaiton is very similar).
The LS1 will make stupid power with just a cam and bolt ons(450 rwhp on a G5X3 is not unheard of). For that on an LT4, you're gonna need a LOT more work- H/C for sure, maybe a stroker. The simple fact is that the LS1 is a better motor and the C5 is a better chassis. If a modded street rod is your desire and you have the cash, go for the C5. IMHO, this is not even debatable- it's simply fact.
The C5 is better ergonomically, has a better suspension setup (true dual A-arms front AND rear), has a much stiffer chassis, has a much more mod-friendly motor, and has a TON more aftermarket support at the moment. Some people (especially on this forum) will disagree with me, but I think they're biased towards the C4 for other reasons.
The LS1 will make stupid power with just a cam and bolt ons(450 rwhp on a G5X3 is not unheard of). For that on an LT4, you're gonna need a LOT more work- H/C for sure, maybe a stroker. The simple fact is that the LS1 is a better motor and the C5 is a better chassis. If a modded street rod is your desire and you have the cash, go for the C5. IMHO, this is not even debatable- it's simply fact.
The C5 is better ergonomically, has a better suspension setup (true dual A-arms front AND rear), has a much stiffer chassis, has a much more mod-friendly motor, and has a TON more aftermarket support at the moment. Some people (especially on this forum) will disagree with me, but I think they're biased towards the C4 for other reasons.
They do sell a lot of aftermarket gear for C5. I saw a video on swaping manifolds to long tube headers and It was joke. It was so easy and simple that maybe it took a minute to position both headers.....try that in a LT1
However I enjoy my C4 and when the time comes I'll go for a C6. They look more "CORVETTE" than C5. The C5 need to get in the stairmaster...ha ha ha