Guys. Have not been looking at 1972's due to lower power but what kind of performance comparison can I realistically expect on a 72 454 or LT-1 to their 70-71 siblings????

 

The '72 454 has all the potentials to eat the LT1s for dinner, but the GMs choked it with the tiny camshaft and all the emissions stuff, needless to mention the ultra-restrictive stock exhaust.

 

The rating system changed.

 

Hi ts,
I think the differences are really between the 70 and the 71-72 models.
For me the 71-72 engines seem a little less 'eager' because of the drop in the compression ratio.
I still need to stop and listen to a 70 LT-! start and idle... for me it's an unforgettable sound. You know immediately there's something serious going on under that hood. 71-72.... not QUITE so much.
Regards,
Alan

 

the 1970 LT-1 is considered by many to be the best small block engine GM put together in that era.......{neat stuff inside} The 70 Vette and the Z-28 Camaros benefited as both models received them.......the other two 71-72 were as Alan indicated, .......not so good, much milder......and the sound is nasty....I have one in my 62 since 1970.....but thats me, I luv um

 

1972 454, 270HP and a ton heavier

1970 LT-1, 370HP

you can do the math........

 

Well, that is kind of what i am getting at. I was NOT even considering 1972 cars until i foind something interesting online. My top choice is a 1969 or 1970 and have driven a 71 LT-1 and it was acceptable, but although rated at 270HP, the 72 454 still has 455 lbs torque, so i'm wondering how it really FEELS to drive. The look of the early C3's is still there, it's the performance I am having a hard time getting past.

 

Cmon. You know they were rated differently. Definitly the 70 was better than the 71-72 but not by a whole lot. The exhaust was so restrictive on all these motor it is rediculous. Put a set of headers and good exhaust and they will behave totally diffeerent.

The LT1 is a higher end screamer the 454 is a boulavard cruiser. Which one do you want.

 

I have both of them, .......

 

Get the big block

Takes very little to make them run hard youll love the torque everywhere you just wont get with the LT1. LT1 was a great little motor but if you like power youll be bored with it in a few days;Werent as fast as they sounded.

 

As mentioned, you have to careful when comparing HP and TQ ratings amongst these years because the rating method was changed from Gross to Net figures starting in the 1972 model year.

So rating method for 1970 and 1971 - Gross; for 1972 - Net.

The real big difference for performance amongst these years is that starting in 1971, engine compression ratios dropped for all engines to meet emission requirements. This did affect performance. But not as much as people think when you look at old magazine articles.

The best way to compare, lump the '71 and '72 LT1 and LS5 engines together (they are the same), use the 1971 gross numbers and compare them to the 1970 gross numbers.

LT1 HP (Tq)
'70 370 (380)
'71 330 (360)

LS5
'70 390 (500)
'71 365 (465)

As you can see, the drop in compression (which affects '71 & '72) cost about a 10% loss in power on average. A positive, you can run lower octane fuel.

As someone mentioned, the LS5 could probably be easily modified for some extra HP. The LT1 is probably at its potential. Tuff call, the Tq and mystic of a big block, or the probably the more balanced LT1 package with that sweet sounding solid cam and factory holley.

If it were me, I would look for the best car I could find and afford, that is either an LT1 or LS5. I would take either. Also, I wouldn't avoid a '71 or '72 if it were a better car compared to a '70. Good luck.

 

Hi TS,
In your last post you mentioned 69 again. Personally I'd take a serious look at a 350/350 which is a VERY nice motor in a Corvette, too.
It was a GREAT deal in 69, ($131.65), and probably is a great deal in 69cars now too, because most people want (and will pay for) that 427 motor.
Really lots of possibilities available. I think for many owners it's just bragging about rights because the all the horses aren't rounded up to stampede all that often.
Regards,
Alan

 

Just to be clear... The '71 & 72 engines were essentially identical in build and performance. The '72 rating system had changed and the HP numbers lowered, as a result. That was the only real difference between '71 and '72.

 

As far as comparing a '70 LT-1 against the '71-'72, the '70 will get you down the 1/4 mile about 2-3 tenths quicker. Now if you are going to race it every weekend, that may make a big difference to you. I personally would rather have the '71or '72 and have it run on unleaded premium as it was designed to do.

 

LT-1 at it's max potential? Put a set of headers on a LS5 then do the same for the LT-1 and let me know what you think then. I know what will happen guess which one will eat the other for lunch.....

 

yeah I can do the math BUT it is fuzzy math! 1970 HP ratings are GROSS and starting in 1972 the HP ratings are NET-they are very different and NOT equivalent by a long shot-apples to oranges!

Constant misperception that so and so 1970 makes 350 Gross HP and so and so's 1974 makes 250 NET hp so one engine makes 100 HP over the other engine - NOT!

 

Go to the car shows,..see if more people hover around the BB cars or the SB's.

The LT-1 was a snotty SB, but as stated above, the BB platform, with it's 100 more cubes, has much more potential. Simple inexpensive upgrades (starting with the exhaust) and you're in 450+ HP range (gross) without breaking a sweat (or the bank).

In order to extort 450 honest HP from the LT-1, you'll need to open your wallet for valve train upgrades and heads. Even then, you'd have an engine that was much more tempermental and less driveable than the 454 with the same HP.

My opinion,..worth what you paid.

 

No expert on original stuff, but as I read this, I kept thinking that for a purist the above is inportant.

But if you are going to drive and flog this car, who cares what motor it has or which was best back then. Get one with out a motor and do it right today.

My 71 had an LS5, but no more, so it will eventualy get a motor that will put a smile on my face all the time, and probably deliver more than the vintage motors would because I can do what I want to my NOM car.

 

Thanks everyone for the replies. I am looking to compare originally set up cars. I am not going to be buying something that has been tinkered with, or will I be tinkering with it. My intention is to buy something original and perhaps NCRS judge worthy. When I drive the car however, I just want to also have some fun and a smile on my face, so understanding how the engines compare, and more importantly, feel, is important to me.

I was initially only considering 69, 70, 71 either 350/350, 427/390, 454/390, or LT-1's depending on the year and availability of each engine. However, if I read this thread correctly, and other source as well, the 1972 454 was essentially the same motor, and thus would have rated the same 365hp as the '71 if not for the gross to net hp rating change. Thus, I will consider very nice '72 454's. but will take '72 LT-1's off of my list as just not being enough of an exciting engine to drive, although it does have some value for being rare in numbers.

 

I suggest that before you walk away from a LT-1, and how it drives and performes, that you need to drive one.


All of the feed back on this forum cannot replace the actual experience.

Big Blocks make power w/o a lot of expense but are heavy and lower RPM motors unless built to turn up .


Small Blocks require some special parts to make power, especially the LT-1's which are quite different from base small blocks and have many racing parts that allow for, and easily turn up the RPMS fast.

The 35 HP loss in a LT-1 over a 454 in 1971 is made up by the lighter weight and better handling, add in a 3:70 rear end and start saving up to pay for tikets.


In short, either ride in or drive a LT-1 that is being shifted at 6 to 7k RPM'S

Then tell us that they are not exciting.


David