Low gear at 8000 rpm is spinning the hub at 22,000 rpm. I had a low hub explode on a HEMI race car and blew a basketball sized hole in the tranny tunnel. The picture of that “incident” made it on the cover of Mopar Action in the late 90s. lol
I'm suspecting that drum explosion was not while using a 904 and to be honest I don't think I have ever heard of a drum explosion on a 904 with the much lower reciprocating weight.
@@Duster_Garage Which in turn is increased weight and so yes that is the reason.....now a person can choose to spend some money and get a billet steel or aluminum drum in that 727 and all would be fine. Guys that have to run a 727 due to class rules for example stock eliminator all have 904 internals in the 727 case.
I'm guessing taking into consideration the engine this new trans is going behind you aren't looking to spend a lot but if you were aluminum, aluminum, aluminum for significantly less rotating weight which is easy quicker E.T.s and billet shafts are your friend. It is crazy but not surprising to hear and read so many comments about the lack of knowledge in regards to the performance gains of the 904 over the 727 and how much power they will hold when built appropriately. Good video
At some point I plan on building an absolutely bulletproof 904, just not for this engine. Question, are you running a stock planetary in your trans and how many clutches do you have in your high gear drum?
@@Duster_Garage 5 Raybestos High Energy frictions.....3 plus years ago when these trans were done for me they did not have a 6 clutch drum but they did design and produce one and it is now available. Darren is looking into what planetary I have in my transmissions and I will let you know when I find out. Hope that helps a little.
@@Duster_Garage I have 3 transmissions from them and 2 are 2.45 helical gear in factory carrier and the other one is 2.74 helical gear in factory carrier. There is a starting line ratio (SLR) formula that helps determine what first gear is most ideal when taken into consideration things like weight, tire size and rear gear and if you never tried that formula you should give it a try. Have a great day
Only thing I would recommend is to air check each clutch to diagnose and identify problems before you pull it out of the trans using compressed air etc. Is the valve body modified?
You’re right I should have done that before I tore it completely apart. The valve body that was in it had the Trans Go tf2 kit but that vb is in my other trans now and it works great.
I was gonna have a 904 built for the 377 in the Dart but it was suggested that it wouldn't be cost effective for the power level I was looking for plus the transbrake launch
You can shave a little e.t. off by going to a 904. My buddy’s 904 is an almost identical build as mine and it’s behind a 620hp 408. No transbrake though. Billet drums and hardened shafts would probably be a must for that. You’re right that’s big 💵.
It wasn't that the 904 wouldn't be faster but a tenth faster for several thousand more dollars doesn't make sense! And it was the Mopar trans guru at A&A transmission MR Allison!
Plus a 250 plus shot of juice on top of the already 650 on motor that type of 904 would be 10 to 12 k to build! A 727 for 1/2 that is a better place to start
@@377PoisonDART4 Is he the guru? Hmmm didn't know that, lol, well you got to make choices that are gonna start chipping tenths away at some point and from somewhere and most have no idea how to even get the easy tenths and then once kindergarten is over it's time to open the bank account real wide to start knocking the hard tenth's off. I already been there, done it, the easy and the hard but since I refuse to tell a person how great their poorly performing car runs I am not part of that clique of idiots so I should probably keep what I know to myself and have badass cars that OVERPERFORM.
I’m not nearly as familiar with the differences between the 904 and a 727. Is it similar to the differences between a C-4 & C-6, or more of the differences between an FMX & C-6?
@@Duster_Garage The FMX was that “split the difference” trans between the C-4 & C-6. You don’t find all that many FMX trans out there, but they’re usually attached to a 351C.
Excellent video 💯👍🏻
Thank you
Low gear at 8000 rpm is spinning the hub at 22,000 rpm. I had a low hub explode on a HEMI race car and blew a basketball sized hole in the tranny tunnel.
The picture of that “incident” made it on the cover of Mopar Action in the late 90s. lol
Dang! Hopefully you had a trans blanket. I only push her to 6500 rpm but I guess that’s still like 18,000 rpm hub speed.
@@Duster_Garage no blanket until after the explosion.
I'm suspecting that drum explosion was not while using a 904 and to be honest I don't think I have ever heard of a drum explosion on a 904 with the much lower reciprocating weight.
@@moparsareeverything1980I have heard the 727 drum is susceptible to failure because of the larger diameter.
@@Duster_Garage Which in turn is increased weight and so yes that is the reason.....now a person can choose to spend some money and get a billet steel or aluminum drum in that 727 and all would be fine. Guys that have to run a 727 due to class rules for example stock eliminator all have 904 internals in the 727 case.
I'm guessing taking into consideration the engine this new trans is going behind you aren't looking to spend a lot but if you were aluminum, aluminum, aluminum for significantly less rotating weight which is easy quicker E.T.s and billet shafts are your friend. It is crazy but not surprising to hear and read so many comments about the lack of knowledge in regards to the performance gains of the 904 over the 727 and how much power they will hold when built appropriately. Good video
At some point I plan on building an absolutely bulletproof 904, just not for this engine.
Question, are you running a stock planetary in your trans and how many clutches do you have in your high gear drum?
@@Duster_Garage 5 Raybestos High Energy frictions.....3 plus years ago when these trans were done for me they did not have a 6 clutch drum but they did design and produce one and it is now available. Darren is looking into what planetary I have in my transmissions and I will let you know when I find out. Hope that helps a little.
@@moparsareeverything1980yes, thank you
@@Duster_Garage I have 3 transmissions from them and 2 are 2.45 helical gear in factory carrier and the other one is 2.74 helical gear in factory carrier. There is a starting line ratio (SLR) formula that helps determine what first gear is most ideal when taken into consideration things like weight, tire size and rear gear and if you never tried that formula you should give it a try. Have a great day
@@moparsareeverything1980cool, thanks. I will look into that formula
Only thing I would recommend is to air check each clutch to diagnose and identify problems before you pull it out of the trans using compressed air etc. Is the valve body modified?
You’re right I should have done that before I tore it completely apart. The valve body that was in it had the Trans Go tf2 kit but that vb is in my other trans now and it works great.
Is the 904 a stock 318 Transmision?.I haven,t seen part one but love Duster Garage....
Thanks buddy. It was typically found behind slant 6s and 318s. I think in the late 70s and early 80s you could get one behind a 360.
good vid 👌
Thanks man
I was gonna have a 904 built for the 377 in the Dart but it was suggested that it wouldn't be cost effective for the power level I was looking for plus the transbrake launch
You can shave a little e.t. off by going to a 904. My buddy’s 904 is an almost identical build as mine and it’s behind a 620hp 408. No transbrake though. Billet drums and hardened shafts would probably be a must for that. You’re right that’s big 💵.
Whoever suggested not running a 904 behind that engine has zero clue about how to make a car go fast.....you need better advisors
It wasn't that the 904 wouldn't be faster but a tenth faster for several thousand more dollars doesn't make sense! And it was the Mopar trans guru at A&A transmission MR Allison!
Plus a 250 plus shot of juice on top of the already 650 on motor that type of 904 would be 10 to 12 k to build! A 727 for 1/2 that is a better place to start
@@377PoisonDART4 Is he the guru? Hmmm didn't know that, lol, well you got to make choices that are gonna start chipping tenths away at some point and from somewhere and most have no idea how to even get the easy tenths and then once kindergarten is over it's time to open the bank account real wide to start knocking the hard tenth's off. I already been there, done it, the easy and the hard but since I refuse to tell a person how great their poorly performing car runs I am not part of that clique of idiots so I should probably keep what I know to myself and have badass cars that OVERPERFORM.
Do you notice a bigger rpm drop at the gear change with the low gear trans?
I never really never noticed that with my loose converter but maybe with a stock torque converter you might.
I’m not nearly as familiar with the differences between the 904 and a 727. Is it similar to the differences between a C-4 & C-6, or more of the differences between an FMX & C-6?
I’m not real familiar with the Ford trannys but I would think c-4 to c-6.
@@Duster_Garage The FMX was that “split the difference” trans between the C-4 & C-6. You don’t find all that many FMX trans out there, but they’re usually attached to a 351C.
lol yeah that thing will pull in first now hehe.
I hope so, I really want to get some air under the LF tire.