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Transmissions and Rear Ends Three on the tree or four in the floor? Shift it all here.

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  #1  
Old January 2nd, 2018, 07:11 PM
maxwedge maxwedge is offline
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Default 478 Trans options / bellhousing options

May be fixing to purchase a 478 and it has original 5 speed still mounted to engine but curious what if I wanted to run another trans what are my options and whats envolved with the conversion .
I have a 57 Grumman alum van that I wanted to install motor in and
I have a SM-420 & 465 manual trans and curious what I will have to do to mount these or a turbo 400 to the 478 thank you Chris .
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Old January 2nd, 2018, 08:55 PM
Jeannie Jeannie is offline
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Default Re: 478 Trans options / bellhousing options

Moved to Transmissions....
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Old January 3rd, 2018, 01:50 AM
bigblockv6 bigblockv6 is offline
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Default Re: 478 Trans options / bellhousing options

You would be better off using the 5 speed from the 478 engine. Going to a transmission from a lighter duty truck would involve the light duty bellhousing and a flywheel from a 379 V6 since the 478 flywheel has 8 mounting bolts to the crankshaft and external balancing on the flywheel as well. only the 379 would have the correct smaller diameter flywheel that's compatible with the 478, otherwise a custom flywheel would be necessary but would also need to be balanced with the whole rotating assembly and that's why ended up having done to install my 478 in my 68 K2500 pickup. As far as a lighter duty automatic, Bendtsens transmission adapters may be able to fabricate a custom flexplate with ring gear but not sure if they could put the correct offset weight, I know they have made setups for the 702 V12 that has a 10 bolt flywheel but there is no external balancing on the V12. Go to www.transmissionadapters.com. Included in this post is a pic of my custom built 478 flywheel.
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Old January 4th, 2018, 03:06 PM
maxwedge maxwedge is offline
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Default Re: 478 Trans options / bellhousing options

WOW great looking flywheel
So basically I have two options run original 5 speed or get custom flywheel correct ?
From what I read the 379 flywheels basically dont exist correct ?
Thanks Chris
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Old January 5th, 2018, 12:16 AM
bigblockv6 bigblockv6 is offline
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Default Re: 478 Trans options / bellhousing options

Unless you can find a used 379 flywheel which are ultra rare but I've heard of people finding them. A custom flywheel would be the other alternative but at that point you would have to tear down the whole engine so the rotating assembly would be balanced together with the flywheel. In my case considerable weight had to be added to the flywheel as well as the front pulley because I chose to stay with the light duty water pump & timing cover housing for my K2500 pickup. If there's nothing wrong with the current 5 speed setup then you will be better off and save a good chunk of money.
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