When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I owned and raced my LT-1 for 30 years. I'm ready for something "different". Hence the LS6 454 BB build.
But I think that I may miss the HUGE mid-range power surge my LT-1 had as it screamed for the redline. This is so strong at 3000 (530 TQ) that it won't feel like a surge, more like a locomotive!
My LT-1 only made 300 or so TQ at 3000 rpm, but then it shot like straight up. The acceleration was like climbing Mt Everest! As the revs built....More....more.....more.... It was fun! It felt like it would never stop. Fast but not super fast. A lot of fun. This BB will have a completely different feel and will feel like almost TWICE the engine at 3000 rpm! (530TQ vs 300TQ) "Who needs to downshift...not me!" Hah-Hah!. I didn't dare get caught too low in rpm on the LT1. It did not make peak TQ til 5000. This one peaks at like half of that rpm.
It'll rev good to 6K. (but never 7K like the SB) . This one will just feel "different" and it may take a while to get used to it.
What it will be: 500 HP, really fast (12s?) more TQ than tires, and have that gorgeous BB hood! It'll have a bass rumble like no smallblock, and drink gasoline like a wino!
If you want an awesome 1/4 mile car with lots of torque, go big block. If you want something that's more likely to handle like a 911 through the curves, find a hi powered small block. An LT-1 would fit that bill.
Having raced both let me say on a 0-70 mph road course an LT-1 would have an advantage. But in 1st & 2nd gear only.
Over that, or in 3rd & 4th gear it is no contest.
I used to go to Pro-Solos with a competitor called the Green Dot Corvette.
He actually had two outwardly identical white C3s fully prepared and ready to go.
Depending on how tight the turns were set up on race day, or how big the straightaway was, he would either un-load his LT-1 SB, or his LS6 BB.
Must have had an awful decision to make!! (Poor guy.)
(And the Porsche contingent usually setup tighter lower speed courses so as not to get too embarrassed by the muscle cars) My LT-1 had no trouble showing them it's heels if there was room to let it loose.
I might suggest going back into history, Car and Driver, R&T, Autoweek and looking up the 0-60 times over the decades.
If we 'throw out' the highest, L-88's m-22, 4:11's and the lowest 1975 L-48 TH350's with A/C. I find it remarkable how close and similar the 0-60 times ARE.
L46 I agree with you they were all pretty close. When all stock.
I believe it is all about traction. Most C3s as well as most musclecars, came OEM with the same skinny 6.5" wide or so tire.
And most C3s could spin them pretty good in first gear, it was just a matter of for how long.
So the 60 ft times for all of these cars (12 yrs worth) would be remarkedly similar (to 30 mph or so)
Any 0-60mph improvement had to happen in the remaining 2-3 sec to 60 and it took a lot stronger engine to make a little difference in so short a time.
Modern wide high performance street tires did not come out until 84, after the last C3.
Now if you have ever ridden in the same musclecar, and then dropped 10" wide slicks under it, the traction difference is incredible! It is NOT double; it is like 3X or 4X.
That's why so many musclecars could suddenly go a full sec or more quicker at the strip. It was all done in the first 60 ft!
Now if you un-corked the exhaust that's when the MPH jumps, but this has a smaller effect on the ET. And some of them jumped by 10mph on open headers vs factory quiet exhaust. This effect was larger on the Big Blocks and the L88s vs the small blocks. They would gain a little less.
A lot of all the revered musclecar's performance was just un-realized potential, at least as they left the factory. You had to know how to tweak them (gears/tires/headers). These days (50 yrs later) the performance out the factory door is already incredible! For example a 302DZ Z28 certainly did not earn it's reputation by turning high 14s in the qtr, like they did when they were stone stock. It needed waay more gear. It required a huge jump from the stock 3:73s to 5.13s to wake that screamer up!
Back in the day (there still is) a formula for HP vs. 1/4 mile time.
I have a vast library of road tests and such. When I review those...another thing that becomes obvious the WEIGHT of their test equipment in those days.
Usually tables show curb weight and weight as tested....often over 250LBS (driver and test equipment.) I estimate that the equipment weighed from 60-100 lbs!
" when tires were skinny and drivers were fat" lol
Back in the day (there still is) a formula for HP vs. 1/4 mile time.
I have a vast library of road tests and such. When I review those...another thing that becomes obvious the WEIGHT of their test equipment in those days.
Usually tables show curb weight and weight as tested....often over 250LBS (driver and test equipment.) I estimate that the equipment weighed from 60-100 lbs!
" when tires were skinny and drivers were fat" lol
Unkahal
If you could point me toward some of the test figures for 0-60, top speed and 1/4 mile results for early C3's I'd find it fascinating.
Back in the 60's 70's R&T had 'indexes' at the back of the mag. Comparing ALL CARS they tested that year...I'd start there!.
Different thread...same kind of stuff.
A gentleman was 'complaining' of how 'heavy' a C-3 is. My comment was, WHAT? it's light! (compared). So I looked up 1970 FERRARI Daytona 375 GTB vs C-3 LT-1
The Corvette was hundreds of pounds lighter!
Okay... whilst I'm educating myself on big blocks - is the low comp 454 from '72 still a bad ***, or just a lot of weight to haul around without the guts to haul it?
Is the difference between a '70 and '72 LS5 chalk and cheese, or much of a muchness?
1971 was the only year GM published both Gross and Net HP/TQ ratings:
So the 71 engines lost say 30-35 HP due to lower compression ratios vs the 70s.. Not that awful. The 71 & 72-74 engines are virtually identical just rated at the lower Net numbers.
And here is a 1971 Magazine article where they compared all 4 engines in the Corvette, with none other than Zora himself. 2 SB & 2 BB. All the engines have a different "personality".
Now this may stir up some interesting discussion but I have seen a few BB automatics smoke the manual cars in the 1/4 mile. Probably because of torque and grip I would guess.
My cousin had a 71 BB LS6 and when I got to drive it he told me to put in first gear and floor it. He then said to shift into second when I reached 60 mph. I asked him at what speed do I shift it into drive and he smiled and said when you wet your pants.
I miss him and his 71.
Ah, those were the days.
David
1971 was the only year GM published both Gross and Net HP/TQ ratings:
So the 71 engines lost say 30-35 HP due to lower compression ratios vs the 70s.. Not that awful. The 71 & 72-74 engines are virtually identical just rated at the lower Net numbers.
And here is a 1971 Magazine article where they compared all 4 engines in the Corvette, with none other than Zora himself. 2 SB & 2 BB. All the engines have a different "personality".
If I understand this correctly, is my logic sound in saying that a '69 L-46 with Gross numbers of 350hp and 380 tq would have greater performance than the LT-1 above?
If so, I'm struggling to understand why the LT-1 is so revered?
Yes you are correct, the 69-70 L46 engine with the 3;70 gear would hang and will be quicker from 0-60- than an Lt-1
at the high end the Lt-1 would be quicker, if the L46 had an aluminum hi rise, holley carb and the stripped BB hood it would be revered like the Lt-1s I would think
The 70 LT-1 had only a few items different than a 1970 L46.
One made 350 HP and one made 370HP.
They were indeed very close in performance.
The LT-1 did have an aluminum hi-rise, a Holley, and a solid lifter cam with about 20 degrees more duration. Other than that they were equally tough and used the same parts and were both terrific engines. The LT-1 also got the cool BB hood. The LT-1 was the ultimate high-performance SB. It was actually very streetable, but could also be raced and would do very well. It was very flexible. It had torque which it's predecessor the DZ 302 did not. It idled a little rougher, and traded off some low end TQ for a high RPM HP surge vs the L46. From experience I would say down 20 TQ and up 20 HP. vs what the "book" says of about 10. With headers and open exhaust they would approach 400HP and go well past 6500rpm. With a different cam, well, they made a great starting point for a race motor. It was the "King of the Hill" for a SB during the peak of the Musclecar era. It made over 1 HP per inch, and was very reliable even at high rpm.
But the two engines are so close you could probably barely tell the difference below 5000 rpm. I'd say the LT1 revs 500-700 higher.
The L46 died in 70 because it was so close to the LT1. And then the lower CR of the 71-72 engines took some HP out of the LT1. Book says 40. But road tests indicate the drop was much less, maybe 25, as the open chamber heads helped get back some of the breathing the compression drop took away.
But the two engines feel different. The L46 is very good, smooth, very competent and revs well. Does everything well. Like a well mannered "Brit". But the LT1 feels very eager, and ready to rev & go, like a dog pulling on the leash. It's got a little bit of that bad-boy attitude. A little snarly. It's got to be due to either the cam or the Holley, or the steep torque curve, but it's a lot of fun! It has about all the cam you could put in a SB without it driving like a race-only engine. It's got good driveabillity & traction. Both of these are great engines. And are pretty fast. In truth they run about as fast as a hydraulic cam BB, but feel way faster doing it.
But none of those three, ever really get ill-mannered, intimidating or scary, or do things to you the way a solid lifter BB, or a true race engine SB can do to your shorts!. These days even some of the 500HP SBs are pretty darn streetable! But they are still scary fast.
The 70 LT-1 had only a few items different than a 1970 L46.
One made 350 HP and one made 370HP.
They were indeed very close in performance.
The LT-1 did have an aluminum hi-rise, a Holley, and a solid lifter cam with about 20 degrees more duration. Other than that they were equally tough and used the same parts and were both terrific engines. The LT-1 also got the cool BB hood. The LT-1 was the ultimate high-performance SB. It was actually very streetable, but could also be raced and would do very well. It was very flexible. It had torque which it's predecessor the DZ 302 did not. It idled a little rougher, and traded off some low end TQ for a high RPM HP surge vs the L46. From experience I would say down 20 TQ and up 20 HP. vs what the "book" says of about 10. With headers and open exhaust they would approach 400HP and go well past 6500rpm. With a different cam, well, they made a great starting point for a race motor. It was the "King of the Hill" for a SB during the peak of the Musclecar era. It made over 1 HP per inch, and was very reliable even at high rpm.
But the two engines are so close you could probably barely tell the difference below 5000 rpm. I'd say the LT1 revs 500-700 higher.
The L46 died in 70 because it was so close to the LT1. And then the lower CR of the 71-72 engines took some HP out of the LT1. Book says 40. But road tests indicate the drop was much less, maybe 25, as the open chamber heads helped get back some of the breathing the compression drop took away.
But the two engines feel different. The L46 is very good, smooth, very competent and revs well. Does everything well. Like a well mannered "Brit". But the LT1 feels very eager, and ready to rev & go, like a dog pulling on the leash. It's got a little bit of that bad-boy attitude. A little snarly. It's got to be due to either the cam or the Holley, or the steep torque curve, but it's a lot of fun! It has about all the cam you could put in a SB without it driving like a race-only engine. It's got good driveabillity & traction. Both of these are great engines. And are pretty fast. In truth they run about as fast as a hydraulic cam BB, but feel way faster doing it.
But none of those three, ever really get ill-mannered, intimidating or scary, or do things to you the way a solid lifter BB, or a true race engine SB can do to your shorts!. These days even some of the 500HP SBs are pretty darn streetable! But they are still scary fast.
Thanks for that excellent appraisal.
It does make me want either a L-46 or LS5 over a base motor though
As a side, the 327/350 looks to be a pretty sweet motor, too.
It's been a while since I've been on here but this conversation seems like fun.....just Grins/Mile comes to mind. Do they pull?....LMAO...er Yes with a smile or two....:-)
10-10-2020, 03:25 PM
