At some point i want to do an all out turbo build and before i get anything started i want to try to find the best trans for the job. I want a manual simple as but if i have to i can go auto prob 904 but i want to know if there is any manual trans that would be able to handle the torque say 600-700ftlbs since my goal is to hit atleast 600hp if i can. Trying to find actual torque ratings that mean anything seems to be impossible since you have people saying i had x trans behind my 440 with a cam and a 4 barrel making an estimated 500hp. That means nothing since a turbo slant makes more torque than hp and has a torque curve of a diesel and they are talking in rough estimations with 0 data to back up how much power they are making.
I really dont want to have to go auto but since i havent figured out what car exactly i want to do the build in i have options. I do know there are bell housing adapters to gm trans but i have never delt with any gm trans before.

I haven't had the best luck with 904s, but I have heard that one can be built up to take some serious power.

If you want a manual trans then decide what kind do you want. A bolt in? Then a 833 is the ticket. An Overdrive bolt in? Then a Od 833 is the ticket. Better gear spacing and a 5 speed? , then you will need some sort of adapter to get anything to bolt up. If you really plan to get to 500+ HP , stay away from the T-5 unless you like to pick up parts.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

904 should work well if you find someone to build it to be strong. If you want a manual 4spd, you can use a well built 833 or 833OD Mopar trans as Rick says. If you want a modern high capacity manual, then the TKO500 or TKO600 5spds should work, or the T56 Magnum 6 spd. You will need to design/fabricate your own adapter to the Slant engine bolt pattern and figure out a strong bellhousing.

I think the easiest way would be to call Wilcap and have them make you a GM trans to Slant 6 adapter kit, then buy a GM bellhousing+clutch+trans kit from the many vendors out there. Wilcap has the designs for that kit and can make it up on request, although it will be expensive unless you want them to make several and do a group buy.

I have plans to build a high HP turbo Slant, and I will likely save up to do a GM bell+clutch+T56 kit behind a Wilcap adapter plate/kit. Prepare to spend something like $6-8k on the trans swap. $5-6k would likely be a minimum for the TKO 5spd path.

Lou

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My personal favourite for turbo trans is a conventional automatic with torque converter.

I have 2 DIY turbo and fuel injection builds. One is a H-D 883/1200/turbo Sportster and the second is Dart with 170 slant six.

Personally I dont like to full power acceleration with the H-D as the boost has to be collected with every gear and the ride is a bit wild. But with my Dart the boost stays continued with gear shifting and it is much better controlled.



Here is a short example of 170 turbo acceleration. At the upper group the yellow is rpm and light blue boost. As seen when the boost has raised it stays constant over the shifting. My 904 is built like "999" with 5 and 4 clutch discs. The converter is custom with about 3000 stall.

The falling light blue curve is the intake air temperature. I have ethanol injector next to turbo and it acts as a chemical intercooler. The light purple curve is the AFR.

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1966 Dart. 170 cu.in. 200 rwhp.

Yes, to support this kind of power reliably, the 904 is by far the cheapest/easiest way to go. This is assuming you can find someone to build it right. lgu32 has it right to build this with the A999 clutch packs and 4-pinion planetary gearsets.

Lou

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I just overhauled a 46re, many parts are the same as the 727, I have an a500 next, and in looking at heavier duty parts such as billet servos and such, I ain't seeing as much out there for the 904/a500 and what I am seeing seems like way more expensive than what I spent on such parts for the heavier trans ....
I am gonna go back and see just what I paid for the equivalent sonnax upgrade parts for the 727/46re to know for sure.

I am following this with intetest because i am currentlyplanning a forced induction build of a 225 for my truck and I am planning on using an A500. I believe all the old 904 upgrades will work in the main trans body. I hope to use parts from an assortment of v8 and slant six 904s to build a stout 904 that can handle the power of a boosted slant. Shouldn't be too hard since I doubt it will make even 200 HP.

I too am considering adding a turbo to my 225 in my truck once it's broken in good "NA". On the fence at the moment.

I used a ~1989 A500 in my turbo Dart for 10 yrs before the turbo and 4-5 yrs after the turbo, and up to about 325 HP. About 50-70k miles on this trans in this car and about 10-15k w/turbo. This was a swap meet trans with unknown mileage and just my $5 homebuilt shift kit taken from an old Mopar mag. I sold it fully working. I would not worry about beefing anything but would do a shift kit and raise the line pressure. It is a big heavy thing and sucks a lot of power vs. a 904, FYI, but it worked well.

Lou

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Home of Slant6-powered fun machines

I am pretty sure a bone stock 904 will handle 200 HP.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

904's can be built for ma$$ive horsepower.

You will spend a lot to get it there but some 9 second small blocks and possibly will's 9 second slant 6 have a 904.

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http://www.youtube.com/hyperpack

Yes, a stock 904 will take 200 HP. Again, I would do a sshift kit and raise line pressure as that is easier on the trans.

Lou

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Home of Slant6-powered fun machines

My trans guy has a 904 with a transbrake living in a low 9 second 496 ci GTX. Only issue they ran into was a broken output shaft. Put a billet shaft in it and it's been golden.

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Official Cookie and Mater Tormentor.

Thanks, Lou. I was mainly planning a stock rebuild of the A500 but using the gears and guts from a 1968 smallblock 904. I need to get all my 904/A500 transmissions up on my workbench and start comparing parts. With luck, that might happen this year.

Can you explain why the A500 takes more power to operate than a 904? My understanding is that the A500 is basically the same as a 904 with the overdrive unit scabbed on in place of the tailshaft housing. I thought most of the normal 904 parts interchanged with the A500, so I am surprised to hear that the A500 takes more power than a 904 to operate. I can see the larger mechanical load when the trans is in overdrive, but in gears 1-3 why does the A500 take more power to operate?