442_Mustang

I am just wondering. Does anyone have a dyno sheet from a stock rebuilt W-30?I am curious at to the true power and torque levels as well as how flat the curve is.

442much

I read (some musclecar mag) that the real dyno HP for the '70 455 was closer to the HP of the LS6. The magazine stated that the LS6 was advertised at 450 HP bit was dynoed to 42?HP. The Hemi 426 came in at 398 HP. The 455 W30 was advertsed at 370 HP but was into the 400's "closer to the LS6". I remember this because all the others (Chev, Ford, Mopar) advertised more than what came up, while the Olds advertised less that what it was.

Where the 442 real shined was torque...over 500 ft lbs. Sorry, can't remember the issue, and since I read so many musclecar mags I can't remember which one it was. I read this years ago but have no first hand experience.

cutlassefi

I wouldn't believe 398 hp for a 426 Hemi for a minute. They were every bit of 500.

LS6's were well over 400 closer to 500. Buick and Olds 455's I've always read were in the low 400's but were known, and rightfully so, for their torque.

Back then there weren't any Musclecar big blocks that were overrated.

MN71W30

I believe it.
If they were 500+ hp they would be 11 second cars. They were high 12's at best with factory manifolds and carbs. A 375 HP Olds 88 should run 14 flat, they would be closer to 15 flat. I had a friend running a LS6 years ago that was suppose to be a pure stock class car. He was cheating with better valve train parts and probably even the cam, he also removed some weight from the car. He ran around 12.50. That would be well under 500 hp.

442much

Well according to the article the Hemi was advertised with more HP than it actually put out...same with the LS6 and the 427 or 428 Ford. The Olds 455 and the AMC were advertised with less HP than they actually put out. They dynoed the engine's and that's what they came up with. Don't know why they'd lie about it.

Eddie Hansen

I believe there was a rule from gm that specified a certain number of horsepower per certain weight? say 10 hp per 100 pounds or 1 horsepower per 10 pounds 375 hp= 3750 maybe it was cubic inches?

Eddie Hansen

saw it again, it was 1 hp per 10 pounds in all cars except the corvette.... or dealer installed engines ie yenko's nickeys, motion, etc

71 Cutlass

442 Mustang,

So far it's a "No", but like you, I'd be interested to know as well.

442_Mustang

Yeah... I'd like to see a nice stock, non enhanced fresh engine dynoed. Are they a legit 500 ft/lbs? and I asked my engine guy about why the Chev engines seem to be listed with a higher hp rate than the ponts, buick, or Olds. Ford seems like they were rated a lot lower than a comparable chev.

MN71W30

We should consider the net rating difference like they are rated today with the accessories in place.
I raced in some pure stock classes back in the late 80's It seems the cars were less modified back then. Most 65-71 442's were mid to high 14's, So were the GTO's. I raced a one owner unmolested 69 W32 and he would run 14.3 or so. I beat a 440 6 pack Charger with my 68 442 W30 and I got beat by an old guy in a 70 Torino 429. I can still see that old fart passing me at the end, because he fell asleep at the lights. My friends 69 442 Convertible ran a 14.65@96mph in pure stock form. Not too many cars in the 13's. Hp can be calculated fairly closely with some formulas on line. I checked my 96 Roadmaster that would run a 15.0 and it came up right at the advertised net hp rating of 265hp. My 68 W30 was around 325 HP net.

88 coupe

Not likely anyone would bother to dyno a stock (factory specs) rebuild, except as a baseline for evaluation of future modifications. Not a good idea, as factory specs are not the best foundation for a modified engine.

As to factory dyno numbers, they had little to do with the actual production engines or their rated/advertised/published numbers. Torque specs were probably accurate, as there was no reason to "adjust" them.

In those days, NHRA stock classes were determined by dividing the shipping weight (verified at tech inspection) of a particular model, by the advertised horsepower of its engine. Manufacturers simply manipulated the "advertised" figure in order fall into the most advantageous class. In competition, the actual power of those NHRA "stock cars" were tweaked to a significantly higher level than when they left the factory. For example, a simple advance curve alteration, properly done, could have been worth 2-3 tenths of a second.

In reality, except for tuning purposes (and bragging rights), engine dyno numbers are not nearly as accurate as time slips.

Norm

71 Cutlass

Hard to believe no one has done a dyno run on their stock set up...even just for kicks or out of curiosity at least.

442_Mustang

I tell you what... After this latest engine of mine, I'd never test run one in the car or on a stand again. Even if it was just a stock rebuild. To have it jetted right, timed right, have good oil pressure, no leaks before I stab it is worth it.I have had to pull a few engines for stupid stuff and this is the first one I have ever dynoed. Well worth it in my opinion

MN71W30

I'm going to give it a try soon on a BBC 498. It'll be my first.

442_Mustang

I had a bum distributor I bought new that we fought for like a week. For some reason, ith shaft was bent and it only would fire on half the cylinders in order. not every other cyl.The way it was backfiring and poping, I figured it was a cam prob or valvetrain. This Olds engine, it was amazing how smooth it was to watch the guy setup and it fired up instantly.Broke in the cam aned everything for me.

BlackGold

There have been several 455 W-30 dyno sessions documented in Musclecar Enthusiast magazine over the years:

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In the May 2005 issue, Gary Riley (Level One Restorations) tested the engine for Randy Reed's beautiful '70 W-30. The engine was all stock, built with 10.5:1 compression and the 328-degree cam used in the manual W-30s.

With factory W & Z manifolds installed, peak torque was 464 ft lbs at 3500 rpm (still rising, if they would've tested lower), and peak horsepower was 391 at 5200 rpm.

With a good set of headers, peak torque was 486 ft lbs at 4000 rpm (again, it might have been higher below 3500), and peak horsepower was 403 at 4900 rpm. The horsepower curve for the header-equipped engine was very flat, being above 375 hp from 4100 rpm to at least 5600 rpm.

**********
In the October 2008 issue, Dan Jensen (of Pure Stock Muscle Car Drag Race fame) tested a factory-experimental, all-aluminum 455. Despite its exotic parts, this engine was built very similar to a 1970 W-30 engine. I'm not sure, but I believe the heads are essentially F heads except cast in aluminum. The only deviations from stock were custom pistons to get 11.0:1 compression (and I suspect to save a little weight), and an Engle 20-22 cam. Duration-wise, this cam is probably very similar to that used in the automatic W-30s (which is actually identical to the cam used in all automatic 442s in 1970), but it has a little more lift than the stock cam. As a guess, I would expect this cam to have upper-RPM potential about equal to the factory 328-degree W-30 cam (except roll off quicker once it starts), but exhibit much better low-RPM response. The engine tune was optimized for best average (not peak) torque and horsepower.

With factory W & Z manifolds installed, peak torque was 517 ft lbs at 3300 rpm, and peak horsepower was 419 at 4900 rpm.

With 6-inch "dumps" installed in place of the manifolds (I'm picturing these to be like zoomies, but the article isn't real specific), peak torque was 524 ft lbs at 3300 rpm, and peak horsepower was 433 at 4800 rpm. I bet a good set of headers would've added another 5-10 hp and 10-20 ft lbs.

**********
I remember another dyno session published, but I can't find that issue. I believe it was a '70 or '71 W-30 built stock for a PSMCDR car. I can't remember what cam was in it. What I do remember was that it was built with a dissappointingly-low 8.5:1 compression ratio but -- surprisingly -- still performed pretty much equal to the factory horsepower ratings. If anyone knows what issue this article was in, please post it here.

442_Mustang

I wonder why they started the pull at 3500 rpm when they weren't sure if the peaks were below that.

71 Cutlass

Advertised HP for the 1970 W-30 was about 375, so the 391 HP is about right on. Great info Brian.

BlackGold

1/ The brake on many dynos has difficulty regulating the engine speed at lower RPMs.
2/ Most dyno customers don't care a whole lot about what happens at lower RPMs. Most race engines are built to launch above 3500 RPM.

455 Olds 442

Really enjoyed reading this thread...