Why the LT1?
- Thread starter Stallion
- Start date
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Brett
Guest
Thanks for the correction, Robert. 350's can get jumbled up in your mind sometimes! I should have remembered they both weren't designated "LT-1's", otherwise, how could you tell them apart on paper, haha. 
Although I swear the LT-1 had a higher compression ratio. You would know though, you know, owning one and all, haha.
And 425 gross? Wow. So the LT-1 was more powerful than the 454? I thought the ratings in 1970 were already gross, and '72 was the year they switched to bhp?
Also, do you know how to calculate bhp in the cars pre-1972? I have always wondered.
Brett
Although I swear the LT-1 had a higher compression ratio. You would know though, you know, owning one and all, haha.And 425 gross? Wow. So the LT-1 was more powerful than the 454? I thought the ratings in 1970 were already gross, and '72 was the year they switched to bhp?
Also, do you know how to calculate bhp in the cars pre-1972? I have always wondered.
Brett
70 vs. 72 454
I was just comparing the torque for the 72 LT-1 and 72 454 and saying that the 454 has more torque and, therefore, better straight line acceleration, all other things being equal.
I'm pretty sure that the big block cars of a given year tended to have more torque then their small block counterparts from the same year. In fact, I can't think of a single case where that rule was broken.
The paragraphs above relate to cars as-delivered only. I'm sure you could build up a 1972 LT-1 with a few performance parts and blow the doors off of a typical big-block from 1972.
Also, I am talking about two Vettes here so both cars are fast, it's just a question of which one is a little faster in stock configuration.
The 1970 454 would almost certainly have higher torque then the 1972 as Chevy steadily de-tuned the engines between those years to make Ralph Nadar and friends happy.
I was just comparing the torque for the 72 LT-1 and 72 454 and saying that the 454 has more torque and, therefore, better straight line acceleration, all other things being equal.
I'm pretty sure that the big block cars of a given year tended to have more torque then their small block counterparts from the same year. In fact, I can't think of a single case where that rule was broken.
The paragraphs above relate to cars as-delivered only. I'm sure you could build up a 1972 LT-1 with a few performance parts and blow the doors off of a typical big-block from 1972.
Also, I am talking about two Vettes here so both cars are fast, it's just a question of which one is a little faster in stock configuration.
The 1970 454 would almost certainly have higher torque then the 1972 as Chevy steadily de-tuned the engines between those years to make Ralph Nadar and friends happy.
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Brett
Guest
Ok, I thought you were comparing the 70's to 72's in that thread. And with the change in horsepower ratings (makes things confusing sometimes--you never know exactly what produced what...), I thought maybe you knew something I didn't in that the 72's were actually more powerful than the 70's.
And yeah, one thing displacement is going to give you is torque, hands down. There is no replacement.
Brett
And yeah, one thing displacement is going to give you is torque, hands down. There is no replacement.
Brett
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Robert N
Guest
69AutoXr, you are correct on the heads and valve covers.
Brett, the 1970 454 was also more powerful than rated. Much of the difference in the cars also comes from where peak hp and torque are reached. Personally, I believe the LT-i is the faster of the 2, though the 454 will give more of a head-snapping rush when punched. As you pointed out, cubic inches will give you that. I am aware of at least one 1970 LT-1 owner that has won a few races against 454s.
Hp was gross rated in 1970, both gross and net in 71 and net in 72.
As to how they came up with the calcuations, I have no idea.
Part of this was insurance related. It is also why the numbers where listed conservatively.
Brett, the 1970 454 was also more powerful than rated. Much of the difference in the cars also comes from where peak hp and torque are reached. Personally, I believe the LT-i is the faster of the 2, though the 454 will give more of a head-snapping rush when punched. As you pointed out, cubic inches will give you that. I am aware of at least one 1970 LT-1 owner that has won a few races against 454s.
Hp was gross rated in 1970, both gross and net in 71 and net in 72.
As to how they came up with the calcuations, I have no idea.
Part of this was insurance related. It is also why the numbers where listed conservatively.
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Brett
Guest
I was looking around on this site, and the LT-1 option was almost twice as expensive as the 454 in '70 ($450 for the LT-1, to $290 for the 454). Very interesting, don't you think---the larger HP package being less expensive. To me, that is just more evidence pointing towards the originally planned high output 454. I have my dad's original owner's manual from his 1970 454, and they list the engine in there as one of the options to choose from. Maybe it didn't pass emissions regulations and they had to quickly cancel it.
That thing would have been a freakin' MONSTER.:BOW
Brett
That thing would have been a freakin' MONSTER.:BOW
Brett
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jmp
Guest
Brett, I'm no expert, but I think it is a fairly accepted fact that the 70 'vette was supposed to have another 454 option -- the LS6. For whatever reason, Chevy delayed this engine until 71, where it was rated at 425 hp (gross) and $1221 (compared with $295 for the LS5 and $483 for the LT1). There's a (contentious) thread around abouts where a new vette owner was trying to determine if his 70 was an LS6, which would have made it one-of-a-kind.
People have been saying that a 70 LT1 was comparable to the 70 454, and there seems to be some question as to whether that was true in 72 as well. Well, according to a Motor Trend article from 1972, the LT1 was comparable:
LT1 vs 454
HP: 255@5600 vs 270@4000
CR: 9:1 vs 8.5:1
0-30: 2.9 vs 3.8 (maybe this is a typo, as the base 350 went 0-30 in 3.1)
0-45: 4.8 vs 4.9
0-60: 6.9 vs 6.8
1/4 mile: 14.3@92mph vs 14.1@93mph
60-0: 116ft vs 122.9ft
The LT-1 in this test had 3.70 gearing, but I don't know 'bout the 454. The 454 was also an auto, which probably affected things.
The article also says that the LT-1 handled better, running 2-3 seconds faster in lap times over the 454.
The one thing I'm not sure about is the torque. The 72 LT-1 is rated at 280@4000 net or 360 gross. The 72 454, in this article, had a listed torque of 390@3200, but I don't know if this is net or gross. I would think gross, but it is kind of odd that the article would mix its measurements like that.
People have been saying that a 70 LT1 was comparable to the 70 454, and there seems to be some question as to whether that was true in 72 as well. Well, according to a Motor Trend article from 1972, the LT1 was comparable:
LT1 vs 454
HP: 255@5600 vs 270@4000
CR: 9:1 vs 8.5:1
0-30: 2.9 vs 3.8 (maybe this is a typo, as the base 350 went 0-30 in 3.1)
0-45: 4.8 vs 4.9
0-60: 6.9 vs 6.8
1/4 mile: 14.3@92mph vs 14.1@93mph
60-0: 116ft vs 122.9ft
The LT-1 in this test had 3.70 gearing, but I don't know 'bout the 454. The 454 was also an auto, which probably affected things.
The article also says that the LT-1 handled better, running 2-3 seconds faster in lap times over the 454.
The one thing I'm not sure about is the torque. The 72 LT-1 is rated at 280@4000 net or 360 gross. The 72 454, in this article, had a listed torque of 390@3200, but I don't know if this is net or gross. I would think gross, but it is kind of odd that the article would mix its measurements like that.
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Brett
Guest
I know it is an accepted fact, I didn't mean to come off that way. I guess I was just trying to make the obvious point that it makes sense they intended to release it. I was kind of having a conversation with myself, haha. I was just hoping someone would know why the engine was canceled. It's a topic I'm very interested in, and no one seemed to be biting. Like I said, my 1970 owner's manual lists the engine as an option, so there is the proof right there. And it wasn't going to be called the LS6, it was the LS7. They are different engines. The LS6 had a 9.0:1 compression ratio. The planned LS7 was supposed to have a whopping 12.25:1 compression ratio, and rated at 465 hp! And just like the other engines, that was probably a very conservative number. None were produced from the factory. Oh what could have been.
I highly recommend the Corvette Tech Data posters, they are a wealth of information.
Brett
I highly recommend the Corvette Tech Data posters, they are a wealth of information.
Brett
J
jmp
Guest
Really? I'm basing most of my info on the following thread, in which everybody was calling the mystery 1970 engine an LS6.
Anyone ever hear of a 70 LS6?
I guess your manual says LS7? That is news! Now, does that mean there was supposed to be an LS6 and an LS7? Maybe we are talking about two different engines here! Ah, well, we'll probably never know.
What are the 'Corvette Tech Data posters'?
jr9170
Well-known member
I have owned many SHARK cars and various MID-YEARS,and driven many others including my friends 427/435 67 coupe and test drove a 70 LT-1 coupe that i almost bought.The 67 is a monster as far as power and torque goes,literally pinning you in your seat.The LT-1 is no slouch either.I was very impressed with its balance of power and handling.I say almost bought one,because i bought a 70 454 conv. instead.I currently own a 91 red/red ZR-1,and a 70 454 blue/blue T-Top(MY 2nd 454 ).I opted for the 454 instead of the LT-1 for the simple reason of the mystique of the big block vettes.But there is also some of that same mystique in owning a LT-1,that is one very impressive S.B. It pulls like a B.B.But as far a kick ass car neither can compare to the ZR-1.Compared to the Z neither one can compare.The ZR-1 has a balance of speed,power,accelaration,handling,braking that would impress any old school vette guy even if they dont like the newer cars....JMHO THANKS JERRY...BTW great website i will be hanging here more often.
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Robert N
Guest
jr9170, you are correct in the fact that the modern ZR1s and Z06s are no comparison to the older vettes. It is amazing what increased aerodynamics and computer aided design can accomplish. All things considered, the fact that both the 70 LT-1 and the 454 can give most modern day cars a run for their money, I am impressed with the 32 year old technology. My LT-1 will be nodified slightly to take full advantage of everything the engine has to offer.
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Brett
Guest
Sorry for the delay of my response--busy weekend.
Yes, the mystery 454 of '70 was dubbed the LS7. There was no LS6 in '70. This is coming from my original owner's manual. The manual lists 5 engines:
Base engine: 350 ci, 300 hp.
L-46: 350 ci, 350 hp.
LT-1: 350 ci, 370 hp.
LS-5: 454 ci, 390 hp.
LS-7: 454 ci, 465 hp.
I also have a Corvette tech data poster that lists the same exact stats. The Corvette Technical Data posters show every single year/model of Corvette, with all prices, specs, engines--you name it. All fitted onto a normal sized poster. Look for them on Ebay. Very nice quick little reference guides. Their info exactly matches my owner's manual, and it has been spot on with every other reference I have seen, so it is very reliable.
I have not read through that entire thread yet (it's long!), but the unreleased 454 of '70 was definitely named the LS-7.
Brett
Yes, the mystery 454 of '70 was dubbed the LS7. There was no LS6 in '70. This is coming from my original owner's manual. The manual lists 5 engines:
Base engine: 350 ci, 300 hp.
L-46: 350 ci, 350 hp.
LT-1: 350 ci, 370 hp.
LS-5: 454 ci, 390 hp.
LS-7: 454 ci, 465 hp.
I also have a Corvette tech data poster that lists the same exact stats. The Corvette Technical Data posters show every single year/model of Corvette, with all prices, specs, engines--you name it. All fitted onto a normal sized poster. Look for them on Ebay. Very nice quick little reference guides. Their info exactly matches my owner's manual, and it has been spot on with every other reference I have seen, so it is very reliable.
I have not read through that entire thread yet (it's long!), but the unreleased 454 of '70 was definitely named the LS-7.
Brett
jr9170
Well-known member
Brett,you are correct the LS-7 was to be a 1970 option and was even listed the 70 owners manual.The other motor that was to be produced but never was built was the LJ-2 that was to be a TRI-POWER 454,to be rated at 460 hp.....JERRY
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Brett
Guest
Here's a Corvette tech data poster on Ebay right now:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2404913008&category=10076
The 2001 version is the most recent I have seen.
Brett
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2404913008&category=10076
The 2001 version is the most recent I have seen.
Brett
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jmp
Guest
Brett said:
Ah, yes, I've seen this poster before, at one of my local vette shops. I'm buying one of the ones on e-bay.... Thanks!
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