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Thread: th425, th325, th325-4l performance and modyfying?

  1. #1

    th425, th325, th325-4l performance and modyfying?


    I have searched for information about these transaxles but its very hard to find, but here it seems many uses them with performance engines!

    The idea is to use one of these transaxles for FWD dragracing in a SAAB 99 or 900.

    Here in sweden there are many highperformance saabturbocars with 300-700hp but the problem is that the stock gearbox is very weak.

    These cars weight about 1000-1300kg and uses dragslicks.

    The questions is:

    Which transaxle is most suitable for a fourcylinder turboengine revving up to 7000-8000rpm?

    At which rpm or hp/torque will they need upgrading?

    Are there any shiftkits and raceconverters aviable?

    Where can i buy these parts?

    The idea is to also use driveshafts and hubs from the same car.

    I know that this is a forum for kitcars but please help!


  2. #2

    Re: th425, th325, th325-4l performance and modyfying?

    Or maybe someone knows where i can find information about this?

  3. #3

    Re: th425, th325, th325-4l performance and modyfying?

    TransGo makes a shift kit and trans parts for the Th325 and 425's. I've used several many years back.

    The 425 is similar to a turbo 400 "strengthwise" and when modified can hold up to 500+++ HP. The stock 425 Used in Older Olds Toronados (1966 for example) will easily handle 400+ HP stock. The 325's are basically a Turbo 350 Inside and the later models have overdrive as well. 84 and Up Eldorados / Toros and Buick Riviera usually have the overdrive and can be spotted by the "4-speed Automatic" badge on the trunk of the car (and of course the OD on the shift indicator). 400+ HP from the 325 is no problem at all.

    Try searching TransGo. I'm sure they still make the kits. There are other makers of kits, sprags, etc for the Th325's and 425's

    Previous Builds: AF - 308 Replica w/ V8 & GM F-body Testarossa Replica
    Current Toys: 308 V8 Project #2, 91 V-12 Jaguar XJ-S Coupe. 1983 Hurst\Olds, 1979 Trans/AM - 468CID Bracket Car.

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