12 Second N/A Slant 6?
All you need to do to a NAG1 is put a billit stator convertor in it & go race.
The creep characteristics of the billit stator TC will allow streetable stal speeds up to 4000 RPM & more. The TC in my car is rated for 4400 RPM but my weak little old 5.7 only flashes to 3600 but unless you get a bit too quick on the throttle you never know it's there. The TCM lock-up parameters also help streetability & fuel mileage.
It already has a manual slap shift feature (as well as after market paddle shift) or you can let is shift itself in drive. In the stock configuration all you have to do is bump the shifter right for upshift, left for downshift.
Unless you are going forced induction W/800 HP or more, no need to open it up, just run it. I was making about 530 HP @ the crank N/A & hitting it W/a 175HP shot of juice. Never a bit of trouble out of the transmission. I'm still running it W/just over 80K miles on it. Other than swapping a valve body, the pan has never been off.
Guys running forced induction strokers once they were getting over the 800 crank HP level were starting to experince failure.
Mercedes designed these transmissions to hold uo to the big AMG "Compressor' (supercharged) models.
Want a streeetable gear ration that will work well on the strip? Want to have air conditioning & kick a$$ sound system in a car that you can drive across the country to drag race?
Put a 2.93 axle ratio out back & you have 4.13 FDR in 3rd gear, 2.43- in 5th
Put a 3.23 in & the ratios are 4.55 & 2.68
A 3.31 gives you 4.66 & 2.74
A 3.55 gives you 5.00 & 2.94
Will it outperform a Torqueflite on the track? No, of course not, but it will do just as well aside from a bit of a weight penalty, will stand up far better when comparing stock OEM assemblies & allow a very streetable combination.
If you want to have your cake & eat it to, a NAG1 will deliver.
If there was a way @ the present time to run a NAG1 in an "A" body I might go a whole different direction W/my Valiant.
Just throwing this out there as a "what if"?
What if we looked at some of the not-so-obvious situations that we have been discussing here, looking at some of them from a different perspective to gain new insight into some not-so-cut-and-dried results we are used to.
It might be interesting to examine a couple of situations using arguments that may have gone unnoticed or even ignored, previously.
For example, your enlightened comments about NAG transmissions surely were spot on, and were well-researched and very informative.
But, from a different perspective, let's look at THIS car (a video I am sure you've seen before.)
[ame="http://www.youtube.com/watch?v=7QzUfV8iTpQ"]Turbo Slant Six 10.74 @ 127 mph 7-19-10 - YouTube[/ame]
By the way, that car has a power-eating 727 in it.... With a 904, it would likely go 129.... or, maybe even 130.:D
That car has been tested with a variety of rear-axle ratios and it has been found to run quicker and faster through the quarter-mile with a 2.76:1 rear axle ratio than any other set of gears. Tom Wolfe's 500+ horsepower 3,300-pound '70 Dart discovered the same thing. Turbocharged slant sixes benefit (power-wise) from being "held back" with low-numerical gears in the rear end. That, of course, gives them great highway cruise capability with no penalty at the race trick (drag strip.)
An overdrive in this case, becomes a non-issue; a well-built 904 fills the bill, nicely, since the final drive is so Bonneville-like.
Add to that, the fact that most turbo motors do not work well with a lot of overlap (it allows the boost to be blown out a still-open exhaust valve, as you well know,) and this dictate (that mandates short duration to minimize overlap,) makes for an engine that idles a lot like a stock slant six.
Smoothly and quietly...
These engines to which I refer, are built on a long-stroke platform that was never designed for high rpm capability. Most turbo slants in the 500hp range don't run well at high rpm's (I'm talking power output, here,) so strong valve springs with their attendant heavy, sometimes-damaging loads on valve-train components such as rocker arms and push rods, are not necessary, thus, ensuring a long street life for these components.
Turns out that RPM, not cylinder pressure (excluding detonation) is usually responsible for a lot of component failures.
The slant six was originally conceived as an aluminum-block engine, and as such was built robust, with strength of the base infrastructure in mind, since aluminum is not as strong as cast iron. After determining that when all was said and done, the aluminum material was not working out, a top-level management decision was made to switch over to all cast-iron construction. They had made 60,000 aluminum blocks before the changeover.
There were some design parameters for the all cast-iron engine that were markedly different from its aluminum counterpart, but a lot of things were left untouched, and those things are what gives the slant its unusually strong construction. For example, the forged steel crank (early models) only has 4 main bearings, but those bearings are the same size as the ones in the highly-touted 426 Hemi.
The cylinder walls and the deck surfaces are unusually thick, as is the deck on the head. I weighed ours; 84 pounds... ugh! But, stiff...
All this robust construction has allowed slant sixes to be utilized in various and sundry industrial applications (fork lifts, etc) and boats, where longevity is important.
That same set of parameters makes it a stellar candidate for forced induction, because it can literally "take the heat" at boost levels where a lot of lesser engines would throw in the towel.
So, we have an engine that has capabilities that include good driveability (mild cam and relatively low rpm requirements for decent power production,) final drive gearing that has the versatility to include both highway cruising and drag strip forays without changing a thing, and this allows the builder to select from a group of non-dropout Spicer=type rear ends, because he'll never have to change ratios (un-like my supercharged 360 Magnum , wherein I need a 4.10 for the strip and a 2.76 for the highway, so I switch back and forth... and that gets old fast...) plus, the Spicer-type (8.25" Mopar and 8.8" Fords,) you find in junkyards are usually geared for the highway, with ratios in the mid-to-high twos.... perfect for the turbo slant. Plus, the 8.25" units are plentiful in Aspens and Volares, and are way cheap, compared to the 8.75 A body housings which just seem to get more expensive, as time goes by... :(
All this verbiage is relative to the practical applications that often get overlooked when junior inherits a /6 Duster from granny when she passes on to her great reward; he usually cannot WAIT to yank that relic of an inline six out of there and drop a 360 in its place...
Just a different perspective... on an age-old situation.
In a different post, you pointed out that... "the reving ability was why they chose the 170 for NASCAR."
I think the N.A.S.C.A.R. specified rules for that Compact race required that the engine be available in the car.
The 225 was not available in the Valiant for 1960 (the year of the race.) I am sure that if they could have, LEGALLY, the Chrysler engineers would have opted for those other 55 cubic inches, regardless of the 170's ability to rev. That's virtually a 33-percent advantage over a 170... a lot to make up with "revs."
The reason I believe that N.A.S.C.A.R. had such a rule, is that the 240-cubic-inch Ford six from a full-sized Ford, could have been bolted into a '60 Falcon, and with its 4" bore and short stroke, would have made an engine that Mopar would not have found so easy to beat.
But, they didn't and I think that that's the reaoson.... rulz... :violent1:
Thanks for listening!!!!:glasses7:
Here's a picture of one of my "1.6:1" (nominal) rocker arms, or whatever they are... and, a stock, uncut one.
I will make a jig to find out what I have.... but, at any rate, they will give more lift (and, more area under the curve) than stock ones...
I just hope they don't break. My valve springs are only 115# on the seat and 330#open... But that's all that's needed at the low red line we'll run.
We'll see... talk's cheap... LOL!:coffee2:
