Th400 upgrades????? Aluminum drums??

Discussion in 'Race 400/430/455' started by Bens99gtp, Sep 10, 2020.

  1. Bens99gtp

    Bens99gtp Well-Known Member

    debating on buying aluminum forward and direct drums to free up weight inside the trans........anyone done these, if so what kind of gains did you see....any durability issues?
     
  2. hugger

    hugger Well-Known Member

    supposed to be around 17lbs of savings iirc,..thats alit of rotating mass
     
  3. Bens99gtp

    Bens99gtp Well-Known Member

    Is it that much.....i though it was like 5ish for the forward drum and like 3.5ish for the direct......i think the direct will give the most improvements as it has to be brought from a stop change directions and brought back up to speed on the 1-2 shift.


    I know ati has a lightened output shaft for reasonable money that saves another 2 lbs...

    But 10lbs of very quickly spinning weight i would think should help
     
  4. BuickGSrules

    BuickGSrules Gold Level Contributor

    Hmm - can that be bought for a 350 too? I will transfer my stuff to a new case soon.
     
  5. Bens99gtp

    Bens99gtp Well-Known Member

    I have not looked but I bet there is,

    I have thought about seeing what a 350 cost to have built or even a 200......i know alot of super stk cars use the 200 for the weight
     
  6. Bens99gtp

    Bens99gtp Well-Known Member

    Kilgore makes a th400 thst he has a redesign for.......and from what I read many ppl drop .5 to .75 from their traditional 3 speed tranny.......but i think it near 4k or more and I csnt swing that
     
  7. dan zepnick

    dan zepnick Well-Known Member

    My trans guy installed aluminum drums in mine probably has to be 8 years ago. I get it freshened up every 3 years. Had it done twice since installed with no wear issues. I think at the time I picked up a tenth but 2 mph. No downshift or braking when slowing down now though.
     
  8. BUQUICK

    BUQUICK I'm your huckleberry.

    Here is a recent article with a before and after test of installing a Kilgore Superlite transmission in a high-10 second Chevelle. This transmission has a pretty extensive list of modifications and the results were pretty underwhelming considering the $4500 cost. Not a very good bang-for-the-buck improvement and the only way to justify this would be if a person was running a heads-up race class.

    https://www.hemmings.com/stories/article/the-spin-doctor


    "We're also going to determine how well this SuperLite works, with a drag strip test using a 10-second Chevelle running a mildly modified TH400 trans and a 10-inch TCI converter. Once it's baselined, we'll replace the stock transmission with a SuperLite and then run it again. This performance comes at a price—the SuperLite TH400 will take a major bite out of $4,500; more if you want a trans brake."

    "The next week offered some solutions, although the weather was not as cool as in the previous sessions. The Chevelle ran its best pass, finally breaking into the 6s with a 6.98 second pass at 99.56 mph. Unfortunately, we were never able to improve upon that time. The closest was a 7.02 at a slower 99.11 mph. This offered only a 0.07-second improvement over our baseline. If we take the differences in calculated quarter-mile times, the best SuperLite quartermile pass equates to a 10.75 compared to the baseline 10.86, which makes it 0.11-second quicker."
     
  9. Bens99gtp

    Bens99gtp Well-Known Member

    There has been plenty of ppl pick up .5 or more with those trans, but they were all much faster than upoer 10s
     
  10. BUQUICK

    BUQUICK I'm your huckleberry.

    If you decide to do the transmission changes, please post your results so we can all see another real world test.
     
  11. Bens99gtp

    Bens99gtp Well-Known Member

    Well I can't do the kilgore. Thats for sure, the drums have been something I have been rolling around in my head with the few loose marbles for a few years......sonething just always seems to take the money first
     
  12. BrianTrick

    BrianTrick Brian Trick

    The lightweight parts are available for both TH350 and TH400. This is how some of the stockers go as fast as they do. If it is race only,it’s fine. I don’t run that stuff because I like to drive everything.
     
  13. Bens99gtp

    Bens99gtp Well-Known Member

    My car is race only, but the 2 aluminum drum are over 1000, just be nice to have an idea of what gains could be possible from the investment
     
  14. BrianTrick

    BrianTrick Brian Trick

    I’m going more for durability and longevity. All Reid case pieces and a bunch of billet parts. It should be about $4k by the time it’s done. Then I have to do a second one for my other car.
     
  15. Jim Rodgers

    Jim Rodgers Well-Known Member

    I use aluminum drums. No issues in 14 years in a TH400.

    If I was doing it over, I would go with a Coan TH350XLT with the small diameter rotating assembly and low volume pump. Trust me, it gets no better than that.
     
  16. Bens99gtp

    Bens99gtp Well-Known Member

    Well that is something to think about dropping down to an already lighter 350 or 200. But they take alot of parts to live.

    I can do a th400 with no issues

    Jim do you recall any provable gains with the aluminum drums
     
  17. Jim Rodgers

    Jim Rodgers Well-Known Member

    No, I started out with it.
     
  18. BuickGSrules

    BuickGSrules Gold Level Contributor

    Jim, do you know of price for one of those?
     
  19. Jim Rodgers

    Jim Rodgers Well-Known Member

    The TH350XLT With the small diameter rotating assembly and all the good stuff will be $4500 or so from Coan, maybe more now. Thats with stock pan, forward manual pattern, no brake, and no clean neutral since I have a factory column shift.

    Contrary to popular belief, it does not take a lot to make a TH350 live behind 900 horsepower. $1200 will get you a SOLID TH350 from Coan that will hold up fine. But the XLT is just tops imo.
     
    Last edited: Sep 24, 2020
    BuickGSrules likes this.
  20. Bens99gtp

    Bens99gtp Well-Known Member

    Well that is something to chew on there, I've always been told the 350 is worth at least a tenth over the 400 in just the weight alone on stk trannys

    I would want a brake.....my 400 has a forawrd pattern shift with brake, I am also column shifting.......but don'thave to stay as i would like to do an air shifter....but 1200 is close to what drums alone would cost me
     

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