Dynoing A 1970 LS6 Chevelle Engine - Lorenzo's Fast Flow
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- Опубликовано: 13 май 2024
- Welcome to Lorenzo’s Fast Flow Cylinders, your one-stop destination for high-performance engine services and restorations in Hulmeville, PA. At Lorenzo’s Fast Flow, we specialize in the maintenance, repair, and enhancement of a wide range of engines, catering to enthusiasts of 4-cylinder Wisconsin engines, iconic hemi engines, powerful performance marines, and classic muscle cars.
In this video we are dynoing a 1970 LS6 Chevelle engine. It was very important to this particular customer to have this engine dynoed because he didn't want any reason to pull this motor back out of the car because the restoration is impeccable.
The Build:
-11:1 PISTON. 10.2:1 WITH CCS OF THE HEAD AND DECK HEIGHT
-242/242 AT .50 CAM LIFT .520
-STAMPED STEEL ROCKER ARMS
-ALL FACTORY PARTS
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Lorenzo's Fast Flow Cylinder
112 Reetz Ave #5891, Hulmeville, PA 19047 (215) 750-8324
Headers make a lot of of difference!
The header tube size used on this dyno are much too big for this engine.
@@noahdunawayYou are so correct!
Correct. If you put factory manifolds on this engine and ran the dyno again, you'd be in the neighborhood of 450hp. The LS6 was NOT overrated from the factory
In 1970, the engines were tested on a dyno to find Gross hp. No accessories no brake. Dynos were not very common back then, and they were not all the same. Some where considered "good dynos".
Yep along with the open air intake with velocity stack and greater than specified timing advance.,,,but on the flip side, going from 11:1 to 10.2:1 compression lost you some HP too
Fantastic, No BS just solid info. I appreciate it!
I remember these engines well from back in the day. Very few of them and they were the absolute monsters of the street. Great vid, no fluff, great numbers. Hope to see this resto in a future vid.
My brothers speed shop friend used to say, put a set of headers,a msd, and a 850 double pumper and that sucka can’t be beat!
Great video. Thanks for a lot of information and not a lot of fluff.
What a beast!
Man, I love big blocks!
I still remember getting out of ITR (Infnatry Training Regiment) in The Corps in '75 and me and my Dad looked at a pristine '70 chevelle SS w/LS6...I had the money to buy it but my Dad kinda counseled against it with me still only being 19. I passed and saved my money and just borrowed Mom's Caprice for a few months. To this day I wish I would have bought it.
I think we all have a similar story ... 🙄
Similar story here. When I first started driving in 1971, My Dad took me used car lots looking for a car. Living just off Woodward ave at 8 mile in Detroit, I was interested in a fast car for the stop light grand prix. I showed Dad a car I wanted at a lot, a late 60's triple black full size 427 Chevy. He said, Hell no, gas is 31 cents a gallon!. He would end up handing me down his '65 Rambler Classic with a straight six, and getting a '66 289 Ford Galaxie for himself. It did turn out to be a lot more practical for my uses., and I've had mostly smaller engined cars since.
Yeah, in 1992 I walked away from a 69 Corvette convertible that I wonder about to this day.
For me it was a 1966 Chevelle Malibu with the L78 396 and the Muncie 4 speed in 1978. Painted Marina blue with the blue vinyl interior. Was being sold by a family friend who had gotten married and with bambino on the way needed a family car. I’d like to think I’d have taken care of it and still have it today, but the odds aren’t great that it, or me, would still be in one piece. Car had way more power than that chassis and brakes were really up to. It just flew. It would ride down the rode at 95 to a 100 with ease. For the day. Truth is, a bunch of today’s nothing special sedans would smoke it in every way, with the air conditioning on. But for 1966 and especially 1978 with smog bullshit in full force, it was a great ride.
My buddy bought a 70 SS Chevelle L6 in 1979....he still has it and has treated very good....really spent most of the time in corner of his shop...all original
Cool to see this, thank you for sharing
Entirely believable. And the LS6 shown here is a full compression point below what it would have come with when new. So, conservatively that would add another 25 hp to an already potent combo.
BTW, I own a '70 Chevelle SS 454. It's the LS5 version. This engine was rated 360 hp in the Chevelle and 390 hp in the Corvette. No difference. So, GM was definitely playing games back in the day.
Also, the factory 14" wheel/bias ply tire combo was totally useless against the torque big block's made. Ask me how I know. 👍😁
100 believe you big fat tires were the best day two modifications.
Advertised at 11:1 and were actually 10.2: when the ccs were measured and the math was done.No extra 25 hp. Most advertised ratios are actually less; back in the day anyway. Impressive power nevertheless.
@@johnsheetz6639 radials > bias ply.
@@danielslocum7169 static was 11;25 on LS6 engines. 10:25 on the LS5.
@@msh6865 advertised. Possibly but most likely not actual. You done the math? Lets have the specs: bore dia.,stroke,piston compression height, piston dome +cc,head gasket cc,combustion shamber cc.
Good job. Glad to see you are doing DYNO videos. I will watch all of them as I get time. Tony S
Thank you Tony S! Please stick with us! More dyno videos on the way
That was an enjoyable video. Thanks for the info.
Nice headers 😉
My all time favorite car with my favorite engine!! The LS6 (at least my big block) liked around 38 degrees total advance, and it would happily buzz up to 7000(+) rpm with no complaints. Of course I was running an “Old School” Edelbrock “Torker” intake and a 850 cfm Holley double-pumper, with oversized jets, accelerator pumps, etc. I had it in a ‘68 Chevelle (no matching numbers here!😄). What a FUN car to drive!!👍😄😄
Wish I still had it…😢🤷♂️
I will never forget racing a 454 , my 350 had him for the first 40 FT. and after that it was like a Freight Train went passed, my 13.7 and 11.2 for the 454 we were both 73 vettes with the usual upgrades to double the HP. Crane Cam, Headers, Holley dominator II intake a 650 double pumper, the 454 did have a Torker manifold Cam Dynamics cam an a 850 Double pumper that poured lots of black smoke out of hooker headers with side pipes removed. He would never say if he had the original dish pistons or the way better flat tops but I just assumed he did.
You beat him out of the hole because a small block revs much quicker than a big block.
@@t.l.robinson2162 My off the line secret was Bias ply tires that bite and dump the clutch at 5000 RPM everyone I raced wanted to do a roll race after seeing rolling burnouts into third gear and i was amazed when my speedometer was saying over a hundred MPH because the rear tires were spinning at that speed but I was only going 50 or 60 in true speed.
And only reason you hopped was because all that gut wrenching torque he was spinning tires until hooked.
Not really. Either setup could have high stall etc. Big block was losing traction off the line
@@antilaw9911 Chunks of Rubber would break of the tread on the Eagle Gt Tires due to the Torque of the 454. That was about 40 years ago, In the summer of 84 we were racing at the Richmond Fairgrounds Circle Track and a 85 Vette with just a couple Hundred miles on it hit the wall on it's second lap. then a 71 LT-1 Crashed in the same spot after getting loose coming out of a corner and fish tailed out of control all the way down the Front stretch, it hit the wall so hard it bounced backward and the momentum of the spinning wheels caused it to the wall again I had never seen a crash like that before.
I wish i still had my 70 Chevelle with the LS6... be worth a lot of money nowdays for sure
Last January at Mecum they were going for 125K and up.
@@josephsouza9951 One went for 105k (before fees). It had sold on BAT in December 2022 for 170k. Someone got a haircut.
Awesome!
Built my 11 to 1 468 after the early big blocks. Went with a 565 lift roller cam wth ab 850 demon carb and full mad ignition. It has a 6400 rpm pill in the msd and pulled hard all the way there. 528 to the tire
BBC is the way to go for big NA power these days for sure. I love the FAST series. 55 years is a long time ago. The aftermarket has really stepped up. Anyone that wants to see CRAZY. This series has cars running mid and low 9s on a factory appearing engine with a shaved stock skinny bias ply. This means exhaust manifolds (no headers and full exhaust). The engines only appear to be stock. Inside all the tricks. Stroked to way bigger inches, roller cam, and every piece "worked". Then full computer control of the ignition mostly done to pull power away in that first second of a run when the skinny tire would have no chance to "hook" at all. It all ads up to CRAZY ASS results that will shock anyone who gets to see what is under the hood as well as look at those shaved "skinnies" for tires. First time I saw it I walked away thinking I'd just seen an example of "magic" doing the impossible to believe.
made a little more power than I anticipated, but no accsesories at all while on the dyno. That will impact the power numbers, significantly in some cases.
Plus headers.
@@hernandocortez6351this rebuild was put together with 10.2 compression instead of 11.1 from the factory....and.muscle car engines of this level back then used 104 octane leaded fuel...no dou😊bt that LS6 chevelles when new could make 500+ horsepower with just adding headers.
That’s pretty healthy for a basically stock LS6. Once you get a good intake and exhaust setup those old Chevy factory cam profiles almost always produce the same HP as TQ in various displacement engines too.
All the ratings from back then were conservative to placate the insurance companies. Everyone knew that the 454 BB would make over 500,hp you just couldn't say it out loud. Thanks for this test.
Yes and no. They often did fudge the numbers to the downside but the real numbers for this engine as Chevy delivered it weren't this good. Throw stock manifolds on it and replace that EXCELLENT AED double pump carb with the factory issue vacuum Holley and this same engine easily loses 50HP from the numbers seen here. Not to say this test is unreasonable as a picture of how things were. Most guys who owned these cars had headers on 'em within the first year of owning the car. The Vacuum carb probably went away pretty quick too. The "stock" Vacuum carb certainly would have delivered better MPG but fuel distribution suffers with a single "squirter". This Mechanical Holley is easily worth 20-25HP at the top of this pull on it's ability to better even up distribution on that stock dual plane intake.
I like it. Gotta like the 500+ HP. We'd always heard these engines were under rated. I'll take your word for the stock parts inside. I will say that the really obvious "not stock" is probably where the extra power is mostly found though. (not that it matters much most guys would have done it to their stock Chevelle almost immediately anyway). Those big tube Headers and that Double pump AED prep'd carb are worth quite a few extra HP and Torque over the stock issue Vacuum Holley at the top end of the range on any BBC engine you'd bolt 'em on to. 500+ HP Still plenty impressive though for very simple, no big deal, bolt on upgrades. Makes it easy to understand why these engines still get talked about as big power makers from back in the day.
Nice Build.👍
Just subscribed to your channel.
Have a great day.
Thanks so much for supporting us! More videos are coming soon
Awesome !! .....With 540 inches of 10.2 actual CR & Solid lifters, probably the strongest Factory Stock motor of 1970...Other 10.25 or 10.5 CR factory Stock engines Deff in 9.5's CR on a good day !!
That illustrates how well GM's modern 454 HO compares with only 8.75:1 compression (438 hp).
All the engines of that era were underrated due to insurance reasons. You couldn't get car insurance with huge horsepower numbers, especially for younger guys. And yes to the below comment, the headers make a big difference.
They advertised hp ratings from a lower rpm. So they technically weren’t underrating them.
it did make 425hp... at 4200rpm... yeah it'll spin to 6k and make power the whole time..... shhhhhh
@@toveryonder1115
I'm 51 ,been around some, but recently realized that they probably grabbed a hp number at a lower rpm than it's actual peak number on some of these engines.
The 426 Hemi was rated as producing 425hp @ 5000rpm but its actual peak was 490hp @ 6000rpm. Peak torque though was correctly rated at 490lbft.
Not true, I was there in 1970.
I snagged one of these engines out of a flat bottom v-drive boat a couple months ago. Haven't decided which car should get it.
This engine is rated at 450 horsepower. Most people do not remember that initially the 427 was rated at 450 horsepower then reduced to 425 horsepower when the 454 was introduced.
The L88 427 actually had 560 hp
No it wasn't the first 3 months of the 65 corvette was rated 450 HP
@@darrellsomers5427 you can Google it it dynoed at close to 600
@@darrellsomers5427 There was no L88 option in 1965. 1967 was the first year and they sold just 20 or so that year. '68 and '69 were not exactly big sellers but Chevy did sell quite a few more in '68 and '69.
A lot of the ratings were at lower points of the horsepower and torque curves. The L88 was definitely a prime example of that, being advertised as a 430 hp engine but really putting out 560 hp. There's a dyno of an unopened, low mile Ford 429 Super Cobra Jet engine that did something like 484 hp with headers, and a 1962 Pontiac 421 Super Duty belting out 488 hp with a factory McKellar #10 cam.
The restoration is impeccable. As long as you forget the engine didn’t come with long tube headers and it was painted orange.
That's all cool and stuff. This begs the question, 'What would it make through the stock exhaust maifolds and the 2 1/2" exhaust system'?
Nice! Did you all run it with full accessories as well?
I was not expecting over 500 horses from a stock LS6
With that double pump carb and headers........ as a small deviation from "stock"..... you should have. People have long talked about how under rated these engines were from the factory. This test is a perfect example of why that was so commonly heard. Nothing in this test is very far away from how most guys would have set up their own cars with simple bolt on pieces. I like this test. It's proof that these motors were 500+ HP capable without breaking into 'em for changes.
Great work! Now can you dyno a bone stock 426 Hemi? Or, my selfish choice, a ZZ502 crate motor out of the box. I appreciate your style. No fluff and to the point. Thanks
Yes on the 426 Hemi if it comes into the shop and the ZZ502, I generally change the cam right away because the power falls off too early.
could of owned one but lived in Phoenix, AC is a must
Don’t forget that they used the SAE GROSS power ratings back then. That meant no air cleaner, no mufflers, no alternator etc. In the early 1970’s they started using SAE NET power ratings, which they still use today. This meant power ratings as the engine was installed in the car. This alone dropped advertised power ratings by about 50 hp.
That basically confirms everyone’s beliefs that the heavy hitting engines of the late 69s early 70s were all under rated for racing and insurance purposes, like a L88 or ZL1 making close to 600 hp at the flywheel
I will never forget the day my friends buick grand national with few mods blew doors off a big block Ls 7 in a gutted impala the impala swore we had hidden bottle nitrous some were /not
Someone has to try to install a modern cam in one of these 250 @ .050s and dyno it.
Is the intake and carb stock? Headers?
Gave you a sub from Upstate New York! Where are you located
Thank you! We are located in Hulmeville, PA 19047
That's not to shabby for just a carburetor on a non late model LS motor. But the LM LS boys are still going to say, I'd still go LM LS.
Cool, but once you add the factory air cleaner, water pump, steering pump, alternator and especially factory mechanical cooling fan; that 519hp is going to drop!
Barely because those engines make so much torque it won't even matter.
Something is fishy, yes the big headers helped but with over 1 point compression less than stock this motor iisn't quite stock???
It is completely stock and un-blueprinted.
@@LorenzosFastFlow How much HP do those Chevelle exhaust manifolds rob? I assuming the owner will be using them.
With full factory exhaust, accessories (including fan), and stock tune, the factory numbers would be really close.
Maybe so. Under those conditions, you're talking about net HP though. Factory numbers were supposed to be gross, which is about how this engine was dynoed.
@@Sherman62 I’m not convinced that big three dynoed their engines like that in the late 60’s. I think the shenanigans they pulled with HP #s was a trend of the late 50’s-early 60’s. If I remember correctly there were some lawsuits and bad press because engines weren’t delivering what the factories advertised, after that they pretty much stuck to net ratings on their own, before it was mandatory.
What heads are on the Engine? 990 cast rec ports?
No, 291 close chamber.
Wonder what the factory manifolds would do.
And a factory air cleaner.
Kill about 30-40 HP
Back in the day when this engine was Dyno tested with the factory manifolds and all the equipment, alternator, etc it made 375hp on the Dyno. There’s always arguments over the power numbers but not all Dyno,s are the same. Cool test. 👍
What casting number are the heads . And camber size .
LS6 heads are 3964291 casting and ~109cc chamber.
@@ChaosViper67 you are correct!
Original 1970 Chevelle LS6 454's (different in build than the 1971 Corvette LS6 or the 'crate LS6' you could get a the parts counter) had closed chamber aluminum heads and a .270 dome piston pushing 11.25 to 1 compression. Otherwise, you aren't building a 'true OEM 1970 LS6' engine...and horsepower estimates yielding approximately 60-hp per compression point shows that GM VASTLY under-rated the LS6's (as other motors, such as the DZ302) by as much as 100-hp (DS302 rated 290-hp, but most dyno runs will show them approaching 400-hp).
33 horsepower from a 500rpm increase??Out of the 1000s of dyno pulls I've witnessed on a stock setup I've never seen that much of a jump in HP from a slight increase in rpm.
More RPM is literally the definition of more horsepower
As well as an increase in total timing to 35*
He also increased the timing on that pull from 30 degrees to 35 degrees.
The L88 427 had 560 hp
I miss leaded gas😅 😂😂
Remove headers but increase compression to 11.1 still leaves HP at 500+ which sounds about right to me for the LS6
Now let's see what the net is😂😂
Makes me jellos that my stock LS3 can only make 455 HP, but that old LS6 will never get 24 MPG.
Why would I want 24 mpg, it’s a monster. Great for a non computer and non fuel injected.
Should have done better than that. Stock LS6 did not have headers. Put factory cast manifolds on it with full stock exhaust and report back.
I think your test is skewed. Prob around 415-420hp. Not great..
Put a water pump on it with the 7 blade viscous clutch fan and a pressure plate or a torque converter. Put a ps pump on it too.
Yes, that would apply to any motor
I'm dynoing the motor that the customer brought me to make sure everything is okay and there are no leaks to go into the car. I was not dynoing the motor to show what the factory LS6 with factory exhaust manifolds, fan, and other accessories would produce power-wise.
Take the dyno headers off
So its not the same compression lol ,the only big block Chevy in 1970 to use a closed chamber head
I knew mine did that! I pissed off alot of Fords! Lol
The L88 made much more power ..the baddest chevy engine then
The LS7 made more power than the L88
@@brgable Hahahah, your hilarious. You must not know much about engines
My old 454 has lower compression, smaller cam, factory oval port heads, 3310 Holley (750 vacuum secondary) and makes more HP & Torque.
I think the factory HP stickers are lying!
Keep in mind, he is using Dyno headers and running it with no accessories. Those 2 things alone are probably with 40-50 hp depending on what the guy actually uses in his car (like exhaust manifolds).
@@broz1969 True, but I'd be willing to bet the actual factory h.p. was more than 450
NHRA legal "Stock" LS-6 454s are over 600+hp.
Yes all G.M. high perf cams had .050 more lift than factory claims!!
@broz1969 I'm not positive here but I believe the 1970 model year engines were rated without any exterior accessories.
Big block chevrolet the do anything engine
For all of you out there who think Factory original parts are best well they ain't .. But for the Number's Gurus who get soaken wet for "Numbers matching" that worth an easy 0 extra HP ...
Looks right. Headers add at least 60, and I've seen up to 100 hp to a big block. So, low 400 hp with factory exhaust makes perfect sense.
Don't forget that AED prep'd Holley 4150. Vacuum carbs are a compromise to MPG. They can make good mid range RPM power too but if you're gonna wind it up at the drag strip. The Double pump shows why you might make the switch. On a Dual Plane manifold a squirter at the back of the carb helps BIG TIME with fuel distribution that's worth quite a few extra HP over the stock carb as well. Regardless of where most of the extra Horse power and torque is coming form specifically........I think it's pretty obvious that 500+ on this engine wouldn't be possible without those headers and that Carb Both. Take one away and you're not gonna see 500+. Take em both away and suddenly 450HP might be in question. He did say this rebuild is little down on Compression vs stock so ...... with that in mind he's built an impressive engine for sure.
Now deduct any power loss from power steering pump, alternator and factory fan.
The heads had to be ported to get that power.
No way. That has the rectangles on it from the factory, they easily make that power right out of the box
I've seen a 427 with 990 heads unported make 680hp. 13-1 compression and a 288@.050 748 lift solid roller definitely helped.
@@thereluctantgearhead4544 All good, carry on.
Nah. I've done a bunch of L72 and L71 and L89 427s with stock factory heads, and they make around 420hp with factory manifolds and side pipes. The side pipes are super cool but cost at least 20 hp and probably more, while the factory manifolds are at least 60hp off headers.
@@bigblocklawyer Yep, I once seen a crate L-88 427 drop almost 100hp with stock Vette manifolds on a dyno compared to a nice set of 2 1/8 primary 3 1/2 inch collector Stahl headers.
In other words your junkyard LS is junk