Engine Flex Plate

Discussion in 'Classic Mustang Specific Tech' started by geostang351, Dec 3, 2013.

  1. Confirmation; an 86 351w requires a 157 tooth, 28oz fly wheel?
    #1 geostang351, Dec 3, 2013
    Last edited: Dec 3, 2013
  2. Well, the 28 oz is important. What year and trans are you putting it in?
  3. The plan is a T5 from a donor 90-93 mustang. The weight balance is for the motor, not tranny....?
  4. Correct, the weight is motor related and the flywheel must match. All 351w's (any year) are 28 oz imbalance. The 5.0's were all 50 oz. Old 302's were 28 oz, but not really designed for a T5. The T5 probably uses a 157 tooth flywheel (none were 164). What you need is available through the aftermarket in 28 oz.
    #4 dennis112, Dec 4, 2013
    Last edited: Dec 4, 2013
  5. ^^this^^
  6. What do you mean "old 302's were 28 oz, but not really designed for a T5"?
  7. I was referring specifically to a change in manufacturing when the original 302 became the 5.0 AND the T5 was first used. The old 302 no longer existed when the T5 came out. The flywheels/flexplates are weighted differently for the 2 motors.

    What was originally known as the Ford 302 began in 1968 and its basic form was used through about 1981. It had a 28oz imbalance crankshaft (the same as a 289) and its other SBF predecessors. In 1982 Ford redesigned the crankshaft counterweights to make it lighter. To make up the difference, Ford needed to use a different imbalance weight on the flywheel/flexplate and the harmonic balancer. (50oz imbalance) None of these are interchangeable between the 2 motors UNLESS they have been appropriately rebalanced.

    The T5 was first available in Fords in 1983. Since the old 302 (28oz imbalance flywheel) was discontinued before then, they never had a factory T5 so no factory 28oz imbalance flywheels were available for it. Luckily the aftermarket has stepped up and now the T5 swap is an easy conversion for the earlier motor.
    #7 dennis112, Dec 5, 2013
    Last edited: Dec 6, 2013
  8. i see... thank you for the explanation...
  9. T5 has nothing to do with the flywheel...you can run the old style 10" finger style clutch with vintage 28 oz flywheel if you wanted
  10. Im not trying to hijack this thread but im going to put a t5 in my 65 coupe with a 302 and the next thing i need to buy is the flywheel. Any suggestions?
  11. what trans do you have now?
  12. ok then you want a 28oz balance factor 157 tooth flywheel. here are six from summit racing that will fit your application. they vary from an inexpensive steel wheel to a high end aluminum wheel. for the street i would go with one of the steel wheels myself. these are all set up to handle a 10.5" clutch by the way.

  13. ok thanks for the advice