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!