| johnmyron | -- 12-03-2010 @ 10:33 AM |
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Want to do more highway driving/cruising with my 53 convertible which is in process of frame off restoration. Is there a significant gain in highway performance, etc by adapting a c-4 or other trans instead of rebuiding the existing fordomatic? Intend to add a mild cam, and possibly a 4 barrel carb.
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| trjford8 | -- 12-03-2010 @ 8:07 PM |
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Your main problem is the rear end ratio. I think the stock ratio for the automatic is 3.55. If you could drop that gearing to 3.25 to 3.35 it would increase your highway speed. Changing to a C-4 won't make much difference as all early automatics are a 1 to 1 ratio in high gear. The advantage to the C-4 would be less weight and is cheaper to rebuild than the original Fordomatic. The downside is you will need to buy the kit to adapt it to the 8BA motor. Personally I prefer the C-4 and have done this adaption on a 40 coupe with 53 Merc motor. It all comes down to personal preference. If you are building a "driver" and not a show car it's your call on how you want to build the car.
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| supereal | -- 12-04-2010 @ 7:31 AM |
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I like Tom's suggestion, but remember that lowering the rear end ratio will affect both low end power and the shift point, which should occur between 13-18 mph. Too much "grunt" can shorten the life of the bands and the clutch plates. It may require bending the throttle valve stop. The stock rear ratio is a compromise to allow decent highway speed, but also a reasonable power when the stop lights turn green.
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