At 400+hp, What kills A904s?

[MRGTX]

Another racer thinking street cars should run race parts....WHY??? I think I'll call it "904 Derangement Syndrome"...There are a lot of daily drivers on here that don't need to be advised to spend $2k on a 904 tranny when a 727 will work better and more reliable for them at one tenth the cost.

Maybe so. The common wisdom used to be that the A904 is reasonably durable, weighs 35lbs or so less, and takes notably less power to turn than the 727. If your motor/traction/application was beneath some arbitrary threshold, it made zero sense to buy a 727 and rebuild and have your driveshaft shortened too all just go slower, burn more gas…especially if they already owned a 904.

Looking at the earlier posts in this thread, some guys have verified that at least in their cases, that set of durability limits to be significantly higher than the common wisdom would dictate.

What I’m saying is that I have zero interest in buying another slush pump in my situation but I could understand why someone would stick it out with the 904.

 

[MRGTX]

Powerglides, C4s and 904s are rich men's toys. They all require a huge investment to not burn up. I think the op is under the impression that a 904 CAN'T make him as happy as a four speed, but the way he refers to it as a slush box tells me that he's never experienced a performance automatic. He should rebuild his 904 with 5 .061 red eagles in 3rd, kevlar band for 2nd, competition shift kit and different 3rd return spring setup if he's shifting at over 6k, and kd set up right. And when anybody asks me if there's a break-in period, I say kick the tires and light the fires.

My distaste for autos is largely because they have taken over the automotive world and the experience of rowing your own gears is getting harder and harder to find.

When it comes to drag racing, the advantages of automatics are significant. Quicker, less abusive on the rest of the drivetrain, more reliable, etc. No doubts nor arguments from me there.

My personal view is also shaped by this growing realization…almost nobody on this forum has a built up, hotrodded Abody that would even come close to the stock performance electric cars that have been on the road for the past half a decade or so. Keep in mind that what constitutes “quick” acceleration is 100% relative. Just looking back to the 1990s, a sub 6 second 0-60 was respectable. 13s in the quarter was legitimately quick. Now, these numbers are within reach of a Hybrid RAV4 soccer mom mobile, they would be humiliated by a base model bar of soap Tesla Model 3 or Y or whatever they call their lower end cars.

So if the primary advantage of an automatic is picking up a couple of tenths in the quarter mile and maybe getting beat by a Tesla by 15 car lengths rather than 20, the driver engagement and fun of a manual transmission becomes MUCH more important. That’s something that an electric absolutely cannot replicate.

My 904 does pretty well. With the outgoing motor, I had it shifting in just the RPM, the shift kit (Transgo TF2) helped it to chirp between WOT shifts satisfyingly. The ratios were acceptable even if there were too few. It has been a good experience. Also, my pops daily drives a Scatpack Challenger with the ZF 8spd and he will throw the keys at me any time I ask. Good lord that thing snaps off shifts in a thrilling way. It’s admittedly awesome. Not sure what other autos would change my mind…

 

['68cuda416]

My distaste for autos is largely because they have taken over the automotive world and the experience of rowing your own gears is getting harder and harder to find.

When it comes to drag racing, the advantages of automatics are significant. Quicker, less abusive on the rest of the drivetrain, more reliable, etc. No doubts nor arguments from me there.

My personal view is also shaped by this growing realization…almost nobody on this forum has a built up, hotrodded Abody that would even come close to the stock performance electric cars that have been on the road for the past half a decade or so. Keep in mind that what constitutes “quick” acceleration is 100% relative. Just looking back to the 1990s, a sub 6 second 0-60 was respectable. 13s in the quarter was legitimately quick. Now, these numbers are within reach of a Hybrid RAV4 soccer mom mobile, they would be humiliated by a base model bar of soap Tesla Model 3 or Y or whatever they call their lower end cars.

So if the primary advantage of an automatic is picking up a couple of tenths in the quarter mile and maybe getting beat by a Tesla by 15 car lengths rather than 20, the driver engagement and fun of a manual transmission becomes MUCH more important. That’s something that an electric absolutely cannot replicate.

My 904 does pretty well. With the outgoing motor, I had it shifting in just the RPM, the shift kit (Transgo TF2) helped it to chirp between WOT shifts satisfyingly. The ratios were acceptable even if there were too few. It has been a good experience. Also, my pops daily drives a Scatpack Challenger with the ZF 8spd and he will throw the keys at me any time I ask. Good lord that thing snaps off shifts in a thrilling way. It’s admittedly awesome. Not sure what other autos would change my mind…

Well if that's the argument then I guess I will just stay cool with my 60's and very early 70's genuine muscle cars and have something that a generation of men built versus government built, way overpriced computer controlled junk that millennials adore......I mean I could personally care less about beating everything on the planet.....motorcycles can easily be faster, diesel trucks can easily be faster, some EV's may be faster..BUT they aren't cool and represent something I am not nor do I want to be.

 

[CudaFactHackJob]

"and takes notably less power to turn than the 727"...wtf does "notably" even mean? I've seen "60 horsepower" listed as the amount between a C4 and C6...Idiots take out a low gear 999 and stick in a New Yorker 727 (along with its low stall converter) in a Duster (with no kickdown) and then claim that all 727s are pigs. I've seen the same anecdotal argument against the th400 compared to the th350. (Some say I'm 'relentlessly persistent', but I take issue with such statements...)

 

[MRGTX]

Well if that's the argument then I guess I will just stay cool with my 60's and very early 70's genuine muscle cars and have something that a generation of men built versus government built, way overpriced computer controlled junk that millennials adore......I mean I could personally care less about beating everything on the planet.....motorcycles can easily be faster, diesel trucks can easily be faster, some EV's may be faster..BUT they aren't cool and represent something I am not nor do I want to be.

Yep. I agree with pretty much all of that. In my personal opinion, the chance to shift our own gears is just one step farther. For some people that part doesn't matter as much or maybe they prefer their autos. That's fine with me. I'm sure not trying to tell anyone they are wrong for what they like. I was just sharing my own thoughts.

I don't know what the heck you mean by electrics "government built." As much as I dislike Elon Musk, the guy is an anti-government oligarch.

"and takes notably less power to turn than the 727"...wtf does "notably" even mean? I've seen "60 horsepower" listed as the amount between a C4 and C6...Idiots take out a low gear 999 and stick in a New Yorker 727 (along with its low stall converter) in a Duster (with no kickdown) and then claim that all 727s are pigs. I've seen the same anecdotal argument against the th400 compared to the th350. (Some say I'm 'relentlessly persistent', but I take issue with such statements...)

What does "notably" mean? A measurable, repeatable result that makes a big enough difference that we would care about it. That's what I meant at least.

As I said, this was (and still is as far as I know), the common wisdom. I don't have access/time/money to test them myself.

After a quick search, I am surprised to see a number of sources quoting an old Car Craft article (that I would like to find..)citing actual measurements comparing various auto transmissions. I imagine that there are significant variables that would impact these results and I don't know how Car Craft did (or did not) try to control for those variables.

These numbers are from the article in Car Craft Magazine:

Powerglide_____18 hp
TH-350________36 hp
TH-400________44 hp
Ford_C-6______55-60 hp
Ford_C-4______28 hp
Ford_FMX______25 hp
Chrysler_A904__25 hp
Chrysler_727___45 hp

 

['68cuda416]

Yep. I agree with pretty much all of that. In my personal opinion, the chance to shift our own gears is just one step farther. For some people that part doesn't matter as much or maybe they prefer their autos. That's fine with me. I'm sure not trying to tell anyone they are wrong for what they like. I was just sharing my own thoughts.

I don't know what the heck you mean by electrics "government built." As much as I dislike Elon Musk, the guy is an anti-government oligarch.



What does "notably" mean? A measurable, repeatable result that makes a big enough difference that we would care about it. That's what I meant at least.

As I said, this was (and still is as far as I know), the common wisdom. I don't have access/time/money to test them myself.

After a quick search, I am surprised to see a number of sources quoting an old Car Craft article (that I would like to find..)citing actual measurements comparing various auto transmissions. I imagine that there are significant variables that would impact these results and I don't know how Car Craft did (or did not) try to control for those variables.

These numbers are from the article in Car Craft Magazine:

Powerglide_____18 hp
TH-350________36 hp
TH-400________44 hp
Ford_C-6______55-60 hp
Ford_C-4______28 hp
Ford_FMX______25 hp
Chrysler_A904__25 hp
Chrysler_727___45 hp[/QUI

Yep. I agree with pretty much all of that. In my personal opinion, the chance to shift our own gears is just one step farther. For some people that part doesn't matter as much or maybe they prefer their autos. That's fine with me. I'm sure not trying to tell anyone they are wrong for what they like. I was just sharing my own thoughts.

I don't know what the heck you mean by electrics "government built." As much as I dislike Elon Musk, the guy is an anti-government oligarch.



What does "notably" mean? A measurable, repeatable result that makes a big enough difference that we would care about it. That's what I meant at least.

As I said, this was (and still is as far as I know), the common wisdom. I don't have access/time/money to test them myself.

After a quick search, I am surprised to see a number of sources quoting an old Car Craft article (that I would like to find..)citing actual measurements comparing various auto transmissions. I imagine that there are significant variables that would impact these results and I don't know how Car Craft did (or did not) try to control for those variables.

These numbers are from the article in Car Craft Magazine:

Powerglide_____18 hp
TH-350________36 hp
TH-400________44 hp
Ford_C-6______55-60 hp
Ford_C-4______28 hp
Ford_FMX______25 hp
Chrysler_A904__25 hp
Chrysler_727___45 hp

I meant in general all the vehicles being built today are essentially built by government standards and regulations and yes I agree that Elon is not pro government.

 

[jimjimjimmy]

"and takes notably less power to turn than the 727"...wtf does "notably" even mean? I've seen "60 horsepower" listed as the amount between a C4 and C6...Idiots take out a low gear 999 and stick in a New Yorker 727 (along with its low stall converter) in a Duster (with no kickdown) and then claim that all 727s are pigs. I've seen the same anecdotal argument against the th400 compared to the th350. (Some say I'm 'relentlessly persistent', but I take issue with such statements...)

I rebuilt a C4 for a guy one time. He called and said it didn't work; wouldn't even move. He said he revved it and nothing. Had a new torque converter he bought off a buddy... So he brings the trans back along with the converter. I said where's the converter? He picks it up out of his trunk with one hand; like an 8" donut...5k stall...His old worn out 302 two barrel couldn't even rev high enough to hit stall.


i wanna hear more about this .

 

[MRGTX]

I meant in general all the vehicles being built today are essentially built by government standards and regulations and yes I agree that Elon is not pro government.

They really do have to follow a lot of stringent standards these days. Usually that just costs more money and makes cars less fun but honestly, I can't say that it's a bad thing overall. Can you imagine if the population today was driving the cars of the 1960s with leaded gas, 10-12mpg, no cats, etc? We would be swimming in smog. I like the arrangement that we have now. A tiny percentage of the vehicles on the road are "historical" and don't have to abide by modern standards. There aren't enough of them to make a difference and we still get to have fun.

The only other thing I'll say is that automakers CAN still make cars that are satisfying, fast, and fun. Go take a test drive in a Challenger R/T (preferably 392 powered) or a basic Camaro SS, Mustang GT. Theyre all incredible. They all get in the mid 20mpg range on the highway, they can all go deep into the 12s without lifting the hood to turn a single wrench. So we have to enjoy them while they last, IMO.

 

['68cuda416]

They really do have to follow a lot of stringent standards these days. Usually that just costs more money and makes cars less fun but honestly, I can't say that it's a bad thing overall. Can you imagine if the population today was driving the cars of the 1960s with leaded gas, 10-12mpg, no cats, etc? We would be swimming in smog. I like the arrangement that we have now. A tiny percentage of the vehicles on the road are "historical" and don't have to abide by modern standards. There aren't enough of them to make a difference and we still get to have fun.

The only other thing I'll say is that automakers CAN still make cars that are satisfying, fast, and fun. Go take a test drive in a Challenger R/T (preferably 392 powered) or a basic Camaro SS, Mustang GT. Theyre all incredible. They all get in the mid 20mpg range on the highway, they can all go deep into the 12s without lifting the hood to turn a single wrench. So we have to enjoy them while they last, IMO.

I do module programming, ADAS, and diagnostics on new cars and that is what makes it easy for me to have ZERO interest in them.

 

[MRGTX]

I do module programming, ADAS, and diagnostics on new cars and that is what makes it easy for me to have ZERO interest in them.

LOL...OK. I can see that you know what you are talking about.

 

[CudaFactHackJob]

Well if CC says it's so...get real! 55-60 hp to turn a C6? That's more than most VW motors. People just cut and paste like it's proven fact. Don't you know by now that he internet is 95% bs? Those old hot rod magazines weren't much better.

 

[CudaFactHackJob]

"10-12 mpg 60's cars"...you weren't there man! Fullsize luxury cars got 20 mpg at a steady 55 mph.

 

[MRGTX]

Well if CC says it's so...get real! 55-60 hp to turn a C6? That's more than most VW motors. People just cut and paste like it's proven fact. Don't you know by now that he internet is 95% bs? Those old hot rod magazines weren't much better.

Not sure if you read what I wrote but personally, I am not accepting Car Craft's numbers as gospel.

Ok, mister relentlessly persistent. Please share your data. If you have data that informs your opinion or any hard information at all that contradicts what has been quoted from the article, I am all ears. If not, we will just lump your comments in with the 95% of the internet BS.

 

[CudaFactHackJob]

Go ahead and lump it. But I'm not the one cutting and pasting other source's bs; YOU ARE.

 

[MRGTX]

Go ahead and lump it. But I'm not the one cutting and pasting other source's bs; YOU ARE.

So you got nothing? I honestly thought you had some kind of basis for your opinion. I'm not being sarcastic when I say that.

Given that, why you have a problem with the cut/paste numbers? I pasted them in response to your question and provided in context, what I found regarding the common wisdom (from both on and off the internet).

At the very least, those numbers are no less credible than whatever you are using for your comments.

 

[CudaFactHackJob]

Fact is, you don't have an opinion. You site others' opinions. The only opinion I have seen you state as your own (of any consequence) was, "slush box" to define your 904. But,but, but....you had it rebuilt by a local shop...

 

['68cuda416]

Fact is, you don't have an opinion. You site others' opinions. The only opinion I have seen you state as your own (of any consequence) was, "slush box" to define your 904. But,but, but....you had it rebuilt by a local shop...

LOL

 

[MRGTX]

Fact is, you don't have an opinion. You site others' opinions. The only opinion I have seen you state as your own (of any consequence) was, "slush box" to define your 904. But,but, but....you had it rebuilt by a local shop...

What does that have to do with anything?!

You seem to have something to prove here. I have no interest in standing in the way of that. You're literally fighting with yourself.

Just because I'm participating in the discussion doesn't mean that my identity and self esteem has anything to do with my automatic transmission and what I do or don't know about it.

Don't play this elitist "I built it myself and you didn't" garbage. It's tiresome. I willingly respect anyone who wrenches on their own stuff, especially when it comes to things I don't know much about, like automatics. I don't know if that's you or not. You've talked a big game but mostly said a lot of disrespectful stuff about other people's choices. That's your business though.

And just to clarify, I am just trying to learn how to not nuke my 904 while I save up and find the parts for the conversion to manual. I've got no dog in this fight.

 

[CudaFactHackJob]

Then where are your questions about the suggestions on parts that have been posted? Are you going to do it or not? "I built it myself and you didn't" isn't garbage (I might be the only one on here with that mindset..), but fact is you came in here seeking info then proceed to cut and paste bs that has nothing to do with your build. I guess that I'm here for all the elitists that aren't afraid of a 904... That's okay if you're too chickenchit to tear into it...I respect that.. But don't blame some lameass shop down the street just because they sold you a bill of goods. And the fact is, your tranny is a dog; that's supposedly why you're in here...And to top it off, there is only one other post besides mine that has actually been helpful to your cause.

 

[CudaFactHackJob]

Keep 'em comin. I think we can hit a thousand by the California sunset!

 

[MRGTX]

Then where are your questions about the suggestions on parts that have been posted? Are you going to do it or not? "I built it myself and you didn't" isn't garbage (I might be the only one on here with that mindset..), but fact is you came in here seeking info then proceed to cut and paste bs that has nothing to do with your build. I guess that I'm here for all the elitists that aren't afraid of a 904... That's okay if you're too chickenchit to tear into it...I respect that.. But don't blame some lameass shop down the street just because they sold you a bill of goods. And the fact is, your tranny is a dog; that's supposedly why you're in here...And to top it off, there is only one other post besides mine that has actually been helpful to your cause.

Yikes.

If your original intent was to help, thank you. If you are here for something else, and it seems that you are, please feel free to do it without me.

 

[Rat Bastid]

"10-12 mpg 60's cars"...you weren't there man! Fullsize luxury cars got 20 mpg at a steady 55 mph.

No one drove 55 in the 60’s or 70’s. No one.

 

[CudaFactHackJob]

I posted more actual helpful information in this thread than everybody else put together. I'm sure there will be benefit for some readers; maybe not the op, but my replies are mostly for those who want real help; weather they reply or not.

 

['68cuda416]

I posted more actual helpful information in this thread than everybody else put together. I'm sure there will be benefit for some readers; maybe not the op, but my replies are mostly for those who want real help; weather they reply or not.

I will make it super simple for you....if someone wants to run a 4 speed for the fun factor, great, I have a couple 4 speed cars and they are fun but I don't race them or even have them in very rowdy street strip cars but some do......in regards to the 904 they are a phenomenal transmission and are way faster than a 727 and safer and I dare say that 90 plus percent of the stock eliminator guys that have to technically run a 727 case have 904 guts on the inside as they are obviously lighter which simply equates to a faster overall package. The argument of it can't live over a certain power level is a moot point as every part of these cars can say the same thing and as power increases things need to be modified appropriately.

 

[MRGTX]

I will make it super simple for you....if someone wants to run a 4 speed for the fun factor, great, I have a couple 4 speed cars and they are fun but I don't race them or even have them in very rowdy street strip cars but some do......in regards to the 904 they are a phenomenal transmission and are way faster than a 727 and safer and I dare say that 90 plus percent of the stock eliminator guys that have to technically run a 727 case have 904 guts on the inside as they are obviously lighter which simply equates to a faster overall package. The argument of it can't live over a certain power level is a moot point as every part of these cars can say the same thing and as power increases things need to be modified appropriately.

That all makes sense, especially in the context of a class where every advantage counts.

I don’t doubt that dollar for dollar, a 727 is stronger, at least at the lower investment level but if I was in a position to compete in any non bracket racing class, I would be inclined to go for the less energy hungry, less massive option given that the 904 could be built to withstand the stresses without reinventing the wheel.

If someone faced with the same challenge came up with a different solution, well that’s what makes racing interesting. I certainly wouldn’t call them stupid for disagreeing.