Looking for DYNO results on a stock 1969 L78
 

I understand that some of you on this site have dynoed a stock L78. My research indicates that these stock engines produced more than 425 HP. https://www.yenko.net/ubbthreads/imag...emlins/eek.gif

Re: Looking for DYNO results on a stock 1969 L78
 

Back in '68 a magazine did an article on three COPO Chevy IIs prepped by Dick Harrell. The stock L78 automatic ran 14.26@101. The prepped 396 with slicks added went [email protected]. The 427 version prepped went 12.05@115 with Jardine headers and slicks. Our L78 Chevelle put about 3/4 of a car length on a friends car that ran 13.3s. Back in the day, I rode in quite a few L78 cars that were considerably slower. From the factory, with retarded timing and emissions jetting, they were downright slow. So was our 427. Balancing, blueprinting, tuning, and all the other little details can have these engines making considerably more power still but that isn't factory.

Re: Looking for DYNO results on a stock 1969 L78
 

I'm all ears on this subject. Would be nice to see different results with header versus manifolds. Re-jetting the carb, etc.

Re: Looking for DYNO results on a stock 1969 L78
 

You need to define "stock"...are we talking as delivered, tuned, blueprinted, etc...?

Re: Looking for DYNO results on a stock 1969 L78
 

[ QUOTE ]
You need to define "stock"...are we talking as delivered, tuned, blueprinted, etc...?

[/ QUOTE ]

No smog, Tuned, blueprinted, No headers
Martin

Re: Looking for DYNO results on a stock 1969 L78
 

Harrell drag test. http://rides.webshots.com/photo/2144...01686729gRaWji

Re: Looking for DYNO results on a stock 1969 L78
 

I'm sure you have the read the old article.."The 13 second grocery getter"....this was a 69 L78 TH400 Nova in as delivered trim as I recall, ran high 13's. Not sure why you would want info with no smog, blueprinted, tuned, but no headers..?? why do all that and run it thru exhaust manifolds..?? anyway, I seem to recall an article about a Bill Thomas blueprint of the original 1965 L78...and it really produced 425hp...I know of a number of 1970 L78 motors that have made similar power on the dyno...but they all used headers. The horsepower on these motors was under rated...but, probably accurate in stock trim. They need to breath...performance tuning and headers are a must to reach full potentional.

wilma

Re: Looking for DYNO results on a stock 1969 L78
 

LOL...you know, these engines *will* actually run, and better yet, they'll even *perform* using the bone stock exhaust manifolds. I regularly see guys post dyno numbers of engines with headers comparable to numbers I've seen for engines with exhaust manifolds, same builds, etc, and all that tells me is the headers are just a band-aid for something else...

We built an L72 for Pure Stock years ago...we rebuilt it to "as delivered" specs, as I wanted to see exactly what a factory L72 would/could do. So, that meant crappy TRW pistons (28cc dome where it's supposed to be 34cc), uncut heads (110+cc chamber where it's supposed to be 105.9cc), didn't deck the block (pistons were all over the place, probably averaged .014"+ down in the hole), original rods/crank/etc, factory blueprint cam...all of this sloppiness got us barely 10:1 compression. Ran it through the stock exhaust manifolds, and it would pull between 425hp and 430hp on the engine dyno, so around 1hp per cubic inch...this engine carried our stock Camaro to mid-12s @ 108+ at a 3750lb race weight, on F70-15 tires. Now, my blueprinted L72 I did the following season, same intake/exhaust manifolds, same carb/ignition, same factory blueprint cam, etc, just a blueprinted long block, soundly put 50+ hp on the first L72...through exhaust manifolds.

So, as delivered, with a simple going over of the jets/timing I'd say you're looking at 1hp/cu-in, or somewhere around 395hp-400hp...blueprinted, 450hp+ pretty easily (I know of a couple L78s that have done this).

Re: Looking for DYNO results on a stock 1969 L78
 

So, are you saying there won't be an increase in HP with headers..?? even on a well tuned or blue printed motor...

Re: Looking for DYNO results on a stock 1969 L78
 

Rob, are those exhaust manifolds you guys run flowed and worked on some? I heard that rumor somewhere that they were even a little lighter than originals. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif Thanks!

Re: Looking for DYNO results on a stock 1969 L78
 

Rob, what kind of jetting and advance curve did you run in that factory sloppy stock 427 to make the 425 hp. I know that just getting those two in the ball park made a difference that you could actually feel. 20-25 hp? A friend still has his '69 L78 4 speed Chevy Nova. He told me that he went a best of 12.8s with headers, slicks and tuning. He said he was beating on it pretty hard to get there too. How about some real world experiences here.

Re: Looking for DYNO results on a stock 1969 L78
 

Rob,

I had a '69 Camaro SS convertible L-78 that I had Bob Harris at Camaro Specialties completely restore. I had him send the engine to his engine shop for a complete stock re-build, still at standard bore, this engine complete with A.I.R. system on an engine dyno put down 389 hp in stock configuration.

Re: Looking for DYNO results on a stock 1969 L78
 

[ QUOTE ]
Rob, are those exhaust manifolds you guys run flowed and worked on some? I heard that rumor somewhere that they were even a little lighter than originals. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif Thanks!

[/ QUOTE ]
Uh, no...that would be the F.A.S.T. (Factory Appearing Stock Tire) class. Our manifolds in Pure Stock must be untouched...we can run a stock reproduction, but they have to be exact copies...and if the repro's are lighter it's news to me...mine are originals, though.

[ QUOTE ]
Rob, what kind of jetting and advance curve did you run in that factory sloppy stock 427 to make the 425 hp. I know that just getting those two in the ball park made a difference that you could actually feel. 20-25 hp? A friend still has his '69 L78 4 speed Chevy Nova. He told me that he went a best of 12.8s with headers, slicks and tuning. He said he was beating on it pretty hard to get there too. How about some real world experiences here.

[/ QUOTE ]
Without looking at my notes, I'm gonna guess I had the timing all in by 2500 or so, with total ~37 degrees...jetting was close on the primaries at 73-ish (stock 72/76, iirc) and secondaries 78 I believe? Probably woulda been a *tad* better with my current carb (blocked rear power valve, different jet setup, fresh rebuild from Eric).

Re: Looking for DYNO results on a stock 1969 L78
 

Got it! I thought you ran that F A S T class. Thanks. https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Re: Looking for DYNO results on a stock 1969 L78
 

[ QUOTE ]
Got it! I thought you ran that F A S T class. Thanks. https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

[/ QUOTE ]
They actually have a Factory Stock (Pure Stock) class at most of the F.A.S.T. events, that uses the same rules as our Pure Stock class, and normally the Pure Stock guys do the tech, so it's pretty much the same faces & rules...but it is definitely confusing!

As for the big hitter F.A.S.T. class itself (Stock Appearing), my plan is to give it a go with my Y-Chevelle...https://www.yenko.net/ubbthreads/imag...ns/naughty.gif

Re: Looking for DYNO results on a stock 1969 L78
 

I get confused here when people are talking about hp. Are we talking about hp measured at the wheels without any type of drivetrain loss correction factor?

Re: Looking for DYNO results on a stock 1969 L78
 

I'm speaking in terms of flywheel horsepower, although I have had our L72 Camaro on a chassis dyno as well...

Re: Looking for DYNO results on a stock 1969 L78
 

[ QUOTE ]
I'm speaking in terms of flywheel horsepower, although I have had our L72 Camaro on a chassis dyno as well...

[/ QUOTE ] Was the rwhp in the 350 range on the stock build?

Re: Looking for DYNO results on a stock 1969 L78
 

[ QUOTE ]
[ QUOTE ]
I'm speaking in terms of flywheel horsepower, although I have had our L72 Camaro on a chassis dyno as well...

[/ QUOTE ] Was the rwhp in the 350 range on the stock build?

[/ QUOTE ]
actually, i believe it was a tick over 370hp @ the wheels...

Re: Looking for DYNO results on a stock 1969 L78
 

a few years ago when I did my 70 L78 motor;dead stock except for: Hooker Comps, recurved orig 2000 distrib, all in @ 3k. Untouched: garbage 569 flat intake,4557 holley (factory jets), 11:1, Block was taken .30, now 408 cu in. It made 422 HP @ 5400 on the dyno. Maybe the extra 12 cubes (over a 396) did a little extra.? although 69 163 intake is MUCH better than the 569 flatty and I was running headers and distrib. My .02

Re: Looking for DYNO results on a stock 1969 L78
 

Has anyone ever done a back to back comparison of the 569 and 163 intakes. I have a feeling that there wouldn't be as much difference as people might think, especially in the rpm range that these engines work best. People wouldn't believe that the rectangular port intake would work on oval port heads. Seems to just fine. Just curious.

Re: Looking for DYNO results on a stock 1969 L78
 

I've got an old magazine with a feature of an NHRA Stock Eliminator LS-6 Chevelle and I was quite surprised to hear them say that back-to-back the '569' pancake was about the same as the '163' high-rise manifold. Now this was with stock camshaft specs and they stated that with a more radical cam and a higher RPM range that the '163' would probably surpass it.

Re: Looking for DYNO results on a stock 1969 L78
 

The stock built L78 in my Pace Car dynoed in the 380's through headers, no smog, no special tuning or jetting.

My stock L72 427, same deal dynoed at 436hp @ 5900 440 tq @ 4100

Re: Looking for DYNO results on a stock 1969 L78
 

[ QUOTE ]
[ QUOTE ]
You need to define "stock"...are we talking as delivered, tuned, blueprinted, etc...?

[/ QUOTE ]

No smog, Tuned, blueprinted, No headers
Martin

[/ QUOTE ]I'm not sure I'd consider blueprinted "stock". Square the decks/index the crank/index lifter bores/make all "holes" perpendicular to crank centerline/"CC" all the chambers.....etc. Basically "fix" all the things that can't be controlled with mass, assembly line procedures.
A LOT of people use the word blueprinted (balanced and blueprinted used in thousands of ads over the years)too loosely. It's HUGE undertaking that involves a lot of areas

Re: Looking for DYNO results on a stock 1969 L78
 

Good thread BTW.

Re: Looking for DYNO results on a stock 1969 L78
 

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
You need to define "stock"...are we talking as delivered, tuned, blueprinted, etc...?

[/ QUOTE ]

No smog, Tuned, blueprinted, No headers
Martin

[/ QUOTE ]I'm not sure I'd consider blueprinted "stock". Square the decks/index the crank/index lifter bores/make all "holes" perpendicular to crank centerline/"CC" all the chambers.....etc. Basically "fix" all the things that can't be controlled with mass, assembly line procedures.
A LOT of people use the word blueprinted (balanced and blueprinted used in thousands of ads over the years)too loosely. It's HUGE undertaking that involves a lot of areas

[/ QUOTE ]
LOL, I'd say I have a *decent* grasp on what it means...and as I posted above, "stock" and "blueprinted" can indeed coexhist within the same conversation, depending of course on the sanctioning body! https://www.yenko.net/ubbthreads/imag...mlins/grin.gif For instance, the class I primarily race in (Pure Stock) originally dealt only with "stock specs", thus it was in your best interest to "blueprint" your engine to factory/AMA specs...the class has since switched to NHRA specs, which are often a loose interpretation of said factory/AMA specs...as for where the class & a couple participants have recently taken this class & said specs, well, I'll just leave that be for now... https://www.yenko.net/ubbthreads/imag...ins/tongue.gif

Re: Looking for DYNO results on a stock 1969 L78
 

There is a whole lot of difference between pure stock & NHRA stock. I know of a 396-375 nhra legal motor that pulls 640 hp. https://www.yenko.net/ubbthreads/imag...mlins/flag.gif