'78 T5 swap

Discussion in 'Transmission & Driveline Topics' started by th3assass1n, Dec 21, 2009.

  1. th3assass1n

    th3assass1n Member

    99
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    Sep 9, 2009
    Costa Mesa, CA
    I have a 78 camaro that had the original 305 but was swapped by the previous owner for a 350 5.7 and now i wanted to swap the original TH350 for a T5 off of a 1988 camaro. Will it match up directly or will i have to modify it?
     
  2. Louich

    Louich Veteran Member

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    Mar 8, 2004
    Arthur, Ontario
    too weak, if you want to take off hard you better not waste your time. They weren't put behind 350's for a reason.
     
  3. fueler

    fueler Veteran Member

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    Aug 11, 2006
    Canada
    I concur, the t5 is a weak tranny behind a 350 but if you are not running a soft compound racing tire it will suffice. The tendency to grenade happens when a engine is over 275hp or if dropping the clutch with drag radials or slicks. Otherwise, it is very livable on a nicely warmed 350 without soft compound tires. One problem you will run into with the swap has to do with the flex plate. A 350 flex plate does not fit a T5 bellhousing so you are going to have to use a 305 starter on your 350 with the 305 flex plate. So first thing to check is if your 350 is dual drilled with both the staggered and straight across patterns for the starter. Some were drilled from the factory and some were not depending on the year of your 350. The staggered is a 350 starter pattern and the straight across pattern is for 305. If your 350 block does not have the straight across bolt hole you will have to get your block drilled or start with a engine that is dual drilled from the factory. There is some other minor hang ups but I would start with figuring the starter first since it usually ends up being the deal breaker.
     
  4. Erics69

    Erics69 Veteran Member

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    Dec 26, 2007
    Winchester KY
    I've always thought that the world class T-5's made from 87' on could handle close to 450hp and it was the pre-87 non world class trannys were the only weak one's. Is this true?
     
  5. Louich

    Louich Veteran Member

    2,412
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    Mar 8, 2004
    Arthur, Ontario
    you wont be running any flex plate, you will need the small flywheel.
     
  6. Louich

    Louich Veteran Member

    2,412
    0
    Mar 8, 2004
    Arthur, Ontario
    no....a guys 383 i know dynoed 280 horse at the back wheels and 400 tq with a tpi and killed 2 wc t5's, one was fresh rebuild.
     
  7. Damon

    Damon Veteran Member

    12,927
    15
    Nov 16, 2000
    Philly area
    Yeah, they're weak. Not like you couldn't run one on the street and have some fun with it, but it won't hold up to much dragstrip abuse.

    No-lift power-shifts and hard lanches against sticky tires chew them up pretty quick. Remember this same transmission was often teamed with the marginal 7.5" GM rear in the back of many 3rd gen F-bodies. When they went to the much beefier T56 trans in the 4th gens they stopped breaking as many transmissions and then proceeded to blow the (largely unchanged) 7.5" rears to smithereens on a regular interval. Chasing the weak link.... it never ends.

    I'd do a T56 swap if I was going to go through the hassle of changing an automatic car over to a manual.
     
  8. ss4ever

    ss4ever Member

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    Dec 16, 2009
    MO
    I put a TPI 355 in front of my stock World Class T5(88-92 F-bodys V8 cars) and it held up fine. My car turned 245hp/325tq on the Dyno. I had just regular street tires and even ran the stock clutch(I would rather the clutch slip than the trans break).


    You can get a flywheel for a Camaro T-5 305 car 83-85 and it will bolt right up to your 350 with no problems as long as your 350 is a two piece rear main seal.

    As for the starter, as mentioned the T5 uses the 153 tooth flywheel, your Camaro most likely has 168t flexplate. The starter needs to match the flywheel, the size of the engine has NOTHING to do with the starter bolt pattern.

    A big problem with the T5 is that in the F-bodys they were clocked 17 degrees from straight up for clearance issues, it puts the shift knob off center in other cars. On my Monte I cut the shifter off just up above the mount and was able to move the shift rod over about two inches and made it fit center in the console of the car.

    The 88 T5 will also have hydraulic master cylinder and slave cylinder to disengage the clutch. You can find a 83(only) T-5 F-body bellhousing and shift fork use it with mechanical linkage or you can modify your car to accept the hydraulic clutch mastercylinder. The clutch slave gets in the way of a lot of different headers, if you are running stock exhaust you should be ok.
     
  9. th3assass1n

    th3assass1n Member

    99
    0
    Sep 9, 2009
    Costa Mesa, CA
    So would it be better to go with the t-56 or t-5? Cuz its not gonna be a strip car just a fun torquey street rod with a few engine mods i just wanted it to get the power and control of the stick shifts as well as the higher gears for the freeway
     
  10. fueler

    fueler Veteran Member

    110
    0
    Aug 11, 2006
    Canada
    If you are going to go through all the trouble of a auto to manual swap, I would haul out the extra bags of money and spring for the t56 trans.

    But before you commit, I would highly suggest you check to see if your 350 block has the 153 tooth starter pattern. Since the t5 & t56 bellhousing is too small to fit a 168 tooth flywheel, you will need the 305 style starter and 153 tooth flywheel. The general only started drilling 350 blocks for both starter patterns at the introduction of the 305. So if your engine is older you will need one of these nifty tools and some tylenol for your headache;

    http://www.goodson.com/technical_support/instructions/SDJ-1.pdf
     
    Last edited: Dec 22, 2009

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