Looking to swap a 1979 Bonanza to an Automatic Overdrive

midgetorama · Oct 28, 2024

My dad has an ultra clean 1979 Bonanza. Now that he's retired he's driving it more and hates the 4.10 gears at highway speeds. I believe it has the NP203 in it since it's full time 4WD and it's paired to a TH400 and 350 ci.

Can anyone recommend the most straightforward swap to an OD trans? I'm not opposed to a new transfer case swap with lockout hubs.

Happy to provide more information on the pickup to help with recommendations. Thanks!

NickTransmissions · Oct 28, 2024

700R4 is the most straight forward and cost effective swap.

ali_c20 · Oct 29, 2024

Welcome from Austria. When I read the title I wanted to answer: Ask NickTransmission.... but I was too late

midgetorama · Oct 29, 2024

NickTransmissions said:
700R4 is the most straight forward and cost effective swap.

Thank you. It appears a 700 can be mated to a 203, though not optimal. Is there a recommended transfer case for this swap also? Thanks again!

NickTransmissions · Oct 29, 2024

midgetorama said:
Thank you. It appears a 700 can be mated to a 203, though not optimal. Is there a recommended transfer case for this swap also? Thanks again!

You're welcome...I'm not sure on the t-case as that would depend on whether you had a driver side or pass side drop for the front diff but a nicely built 700R4, assuming your engine won't be making more than about 500 HP and/or full race, will make for a great cruiser on the hwy while still giving you decent city mileage (i.e you wont give anything up vs a TH350 or TH400).

legopnuematic · Oct 29, 2024

If you go with a 700r4, an NP208 would probably be the easiest solution as they are rather plentiful and came behind 700r4s from the factory.

They are plenty strong.

If you do go to a part time case, don’t forget to get some manual locking hubs.

midgetorama · Oct 30, 2024

It's a passenger side differential and I doubt the pickup will ever have more than 400 hp even the motor is rebuilt or swapped. I guess the search begins for a 700 core and 208 transfer case.

Thanks again for the info!

Looking to swap a 1979 Bonanza to an Automatic Overdrive

midgetorama

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NickTransmissions

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ali_c20

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midgetorama

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NickTransmissions

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legopnuematic

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midgetorama

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