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Passon 855 installed

i had to laugh --- 580 ci --750hp --4.10 gears --- and you are worried about gas mileage -- i take this engine will never see the high side of 3000 rpm --- so this combination was built for bragging rights only --
I don't "worry" about fuel economy, but I drive my car on 200 mile round trips periodically. And I go WOT and shift at 6000rpm every single time I drive it. I run drag radials on the street. Even with the overdrive I consume copious amounts of 93 octane Dino Juice. I beat the **** out of my car, just like the drunken ex felons on the assembly line at Hamtramck would've liked me to.

Just because you drive your weak sauce small block at 5mph below the limit like a grandma to the car show once a week so you can sit in a lawn chair, doesn't mean everyone else does.
 
I don't "worry" about fuel economy, but I drive my car on 200 mile round trips periodically. And I go WOT and shift at 6000rpm every single time I drive it. I run drag radials on the street. Even with the overdrive I consume copious amounts of 93 octane Dino Juice. I beat the **** out of my car, just like the drunken ex felons on the assembly line at Hamtramck would've liked me to.
:thumbsup: :lowdown:
A kindred spirit!
Since I got the Year One aluminum Rallye wheels (8" x 17 front, 9" x 17 rear) I have had a pair of Toyo Proxes TQ drag radials on the rear. I took a guess and shod them with 315/35/17s. After having a bad experience with Nitto 555 drag radials on my 89 Chrysler (Mitsubishi) Conquest TSi in the rain, I was looking for something better and they have not disappointed me for a dual purpose tire.
Lots of reasons why I got the Passon a855, but one is that I have a stroker planned, and while it won't have quite the punch yours does, I don't want to worry about the transmission breaking when I "no lift shift" at the track. (My 18 spline 833 is a backup trans now, just in case) The Holley 6bbl setup works better when you keep it at WOT.
Although my 70 Roadrunner is a real V-code, the engine is a 1971 440, and the purple stripe cam (292°/.509) makes it want to rev to 6,200 RPMs.
Switching to the 4.10s from the 3.54s when I put the 5 speed in was one of the best 2 things I have done to make my car so much more fun to drive! A lot less engine noise at 70ish in 5th on the interstate, and peace of mind turning 2,750 instead of 3,500, and MAN is it a blast to stand on it!
@Beach Goat
Any thread or more information about your build?
 
I got the build done before I was on the forum, and it's a bit of a story.

The car has been in my family for 35 years...my dad bought it in 1983 the year before I was born, for $300 and an intake manifold. I remember it, it was dad's cool loud car. It wasn't in nearly as good of shape, and I believe it had a 318 at the time. He swapped a 440 six pack setup into it, and it ran like that until the mid 90s when his business took off.

He ended up with another Charger, a 68, and 2 1970 Cuda convertibles. All had 500" stroked 440s, making around 800hp on race gas. But the 70 Charger was always special, and he lavished attention on it.

It got a frame off restoration, a no-expenses-spared paint job, a Dana 60 w/4.10s, and a Mopar Megablock 572". It made about 850hp on race gas. It was always his gnarliest car.

Eventually he had to refresh the motor and bumped it up to 14:1 compression, where it made 870hp at the crank on an engine dyno. That's how it was when he sold it to me 2 years ago.

I couldn't afford the $8/gal 110 leaded gas on the street, so I had thr motor yanked and put to 93 octane specs. It's got a much smaller Comp Cam, I dropped the compression to 10.5:1, and I replaced the cracked crankshaft we discovered with a Scat crank. The top end remained an AED 1000 four barrel and Indy 572-13 heads and a single plane, solid roller lifters, and the displacement is now 580". It made 600rwhp, so roughly 700hp at the crank? Maybe 750.

Since then I've refreshed a few interior items, replaced things like the shocks and a few electrical pieces, but other than that it runs like a top. Starts easy, idles happily at 850rpm, and sounds like a volcano fighting a nuclear explosion at WOT. And it can knock down 15mpg when I need it to.

15656178785892072649882.jpg
 
Oh, one hiccup I ran into with the 855.

The aluminum driveshaft didn't like the new higher rpm it was turning, and vibrated above about 70mph. So I had Denny's Driveshaft I'm New York build me a new one, balanced to something like 15000rpm? Higher than the driveshaft would ever see in real driving. It was also abiut an inch longer, because the old driveshaft wasn't the perfect length to begin with.

So if you had a driveshaft built and balanced for turning 1:1 with a four speed, you might need a new one with a higher balance when the 855 has it turning 30% faster in top gear.
 
So if you had a driveshaft built and balanced for turning 1:1 with a four speed, you might need a new one with a higher balance when the 855 has it turning 30% faster in top gear.
YES! I noticed a "new" vibration in the driveshaft that seemed reminiscent of one that went away after I had it worked on by a local shop that has a stellar reputation and I have been to before. He was less than complimentary about the condition of the driveshaft when I brought it in.
I am considering a chrome moly steel shaft.
Anyone care to make recommendations?
I want this to be the one and done driveshaft, providing it never gets damaged and requires replacement.
 
How can a driveshaft turn 30% faster in top gear, especially if it’s an OD? That would mean it turns slower.
 
How can a driveshaft turn 30% faster in top gear, especially if it’s an OD? That would mean it turns slower.
Because of switching from a 3.54 to a 4.10 ring and pinion in my case. I am not going to do the math, but the driveshaft is definitely spinning faster with the 4.10s than the 3.54s. The engine spins slower in 5th gear. When I'm doing around 70 mph the speedometer says 90 mph or so...
I would address that, but the Dakota digital dash calibration is going to resolve that whenever I get it installed.
If there was no change in the ring and pinion gearset, xx MPH would be the same driveshaft speed as before regardless of what gears were in the transmission.
 
Ah! I didn’t see where you were gonna switch to lower rear gears, makes sense now.
 
Oh, one hiccup I ran into with the 855.
The aluminum driveshaft didn't like the new higher rpm it was turning, and vibrated above about 70mph.
Ah! I didn’t see where you were gonna switch to lower rear gears, makes sense now.
Actually 5.7 hemi, @Beach Goat was the OP and he wrote the above quote and I'm not sure why he would say his driveshaft was turning higher RPMs...??
I reread the thread, and he used to have a 4 speed w/4th being O.D. and I didn't see where he changed the R&P. Looks like it always had a 4.10...
So :wtf:
 
Well, guess I should’ve read the whole thread.
 
Actually 5.7 hemi, @Beach Goat was the OP and he wrote the above quote and I'm not sure why he would say his driveshaft was turning higher RPMs...??
I reread the thread, and he used to have a 4 speed w/4th being O.D. and I didn't see where he changed the R&P. Looks like it always had a 4.10...
So :wtf:

If you have an 833 with 4th gear 1:1 and your engine is revving at say 4000 rpm vs an 855 with 5th gear .70:1 and your engine is revving at the same 4000 rpm, your output shaft, drive shaft and 4.10 gears will be going faster with the 855 and I guess that's where he got the 30% faster rotating driveshaft. That is to say, with the same engine rpm and rear gear ratio, the lower gearing in the 855 will allow you to go faster, which is the whole point of having the lower 5th gear ratio, that you can either go the same speed with lower rpm's or go faster with the same rpm's.
 
The overdrive lowers engine rpm but not the speed of the driveshaft. So the driveshaft is effectively spinning faster (by the inverse of the overdrive ratio) at any speed with an overdrive vs a 1:1 final transmission ratio. So you need a driveshaft balanced for a higher rpm (of the shaft, not the engine).
 
Not for the same mph. If nothing changed, just the addition of OD, driveshaft speed is lower in OD for the same mph.

Think of a 10 speed bicycle, in high gear, your legs don’t need to move as fast to keep the same speed, unlike if you dropped down to 4th.
 
The overdrive lowers engine rpm but not the speed of the driveshaft. So the driveshaft is effectively spinning faster (by the inverse of the overdrive ratio) at any speed with an overdrive vs a 1:1 final transmission ratio. So you need a driveshaft balanced for a higher rpm (of the shaft, not the engine).
The driveshaft spins faster w/a .70 OD at 4K RPM vs a 1:1 top gear at 4K RPM. The car would also be going faster, if the R&P was the same.
Beach Goat, you said you had a Passon "3rd gear",
Previously had an 833 hemi four speed with a Passon 3rd gear.
which I assume you mean the Passon 4 speed OD?
There shouldn't be much difference between the OD top gear in the Passon modded 833 vs 5th gear in the 855, right?
 
Not for the same mph. If nothing changed, just the addition of OD, driveshaft speed is lower in OD for the same mph.
Actually driveshaft speed is dependent on rear wheel speed. The driveshaft is connected to the Pinion gear of the Ring and Pinion, and the Ring is connected to the rear axles, so to speak, and thereby the rear tires.
Basically 70 MPH turns the driveshaft at the same RPMs no matter what gear you are in!
Engine speed is lower w/OD for the same MPH.
Got it?
 
Horse ****! If a drive shaft is spinning the same speed for every gear, you wouldn’t be able to accelerate.
 
Horse ****! If a drive shaft is spinning the same speed for every gear, you wouldn’t be able to accelerate.
Not what I'm saying.
70 MPH makes the driveshaft spin at the same RPMs, no matter what gear you are in. In other words if you are in 4th gear at a 1:1 ratio, or in 5th gear at .70:1 or in 6th gear at .50:1 that doesn't change the speed the driveshaft spins at 70 MPH. It only changes the engine RPM at 70.
70 MPH turns the driveshaft at the same RPMs no matter what gear you are in!
The statement above is absolutely true. 70 MPH turns the driveshaft at the same speed no matter what gear you are in! 100% true!
Wagers to follow any further denial....
 
Ok, I actually had to go look this confusing **** up, and you are correct Bio! While I do (now) understand what you are saying, my pea brain couldn’t get around the DS staying the same speed whether it’s 1:1 or :70 OD.

I’m now taking my feet out of mouth!!
 
I’m lost. Disappointed that after waiting 4 years, the 855 in my pals ‘Cuda had to make 2 trips back to Pennsylvania for repair. That math is more in my wheelhouse. SST no issues. That’s 1000 miles in the car and 12000 miles on the truck.
 
Not what I'm saying.
70 MPH makes the driveshaft spin at the same RPMs, no matter what gear you are in. In other words if you are in 4th gear at a 1:1 ratio, or in 5th gear at .70:1 or in 6th gear at .50:1 that doesn't change the speed the driveshaft spins at 70 MPH. It only changes the engine RPM at 70.

The statement above is absolutely true. 70 MPH turns the driveshaft at the same speed no matter what gear you are in! 100% true!
Wagers to follow any further denial....

Isn't that what I explained????????? :)
 
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