Sbc swap in 78 cutlass

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Ribbedroof

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700r4 will require an aftermarket crossmember (or modifications to the original) and a frame extension for the driver's side on your car (and all G body prior to 1984)
 

Shane salon

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Apr 22, 2016
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700r4 will require an aftermarket crossmember (or modifications to the original) and a frame extension for the driver's side on your car (and all G body prior to 1984)
I would like to keep it more simple as possible and the trans my uncle has is a th400 not the 350 i miss understood
 

Ribbedroof

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TH400 will require same mods as 700R4
 

Ribbedroof

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If it's a cruiser not a hotrod, in the long run, the th350 will be way easier to use, and lighter too.

TH400 may require a different flexplate depending on torque convertor used. Starter nose will almost always need to be changed. These are because the TH400 usually uses the large flexplate (168 tooth), and most others use a smaller one (153 tooth). It's been a long time since I was swapping this stuff around frequently, so I'm sure some of the other guys can pick up my slack.

As I recall, some aftermarket flexplates have multiple TC bolt patterns on them.
 

Ribbedroof

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Wellston, OK
If it's a cruiser not a hotrod, in the long run, the th350 will be way easier to use, and lighter too.

TH400 may require a different flexplate depending on torque convertor used. Starter nose will almost always need to be changed. These are because the TH400 usually uses the large flexplate (168 tooth), and most others use a smaller one (153 tooth). It's been a long time since I was swapping this stuff around frequently, so I'm sure some of the other guys can pick up my slack.

As I recall, some aftermarket flexplates have multiple TC bolt patterns on them.
 

Shane salon

Not-quite-so-new-guy
Apr 22, 2016
18
0
1
If it's a cruiser not a hotrod, in the long run, the th350 will be way easier to use, and lighter too.

TH400 may require a different flexplate depending on torque convertor used. Starter nose will almost always need to be changed. These are because the TH400 usually uses the large flexplate (168 tooth), and most others use a smaller one (153 tooth). It's been a long time since I was swapping this stuff around frequently, so I'm sure some of the other guys can pick up my slack.

As I recall, some aftermarket flexplates have multiple TC bolt patterns on them.
I plan on doing this swap for now but come this winter I'm making plans for a different swap it's just a cruiser for now but my next swap I wanna have a car with power something that I can drive on good days and some nights to play
 

Ribbedroof

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Ok anything else that you can think of

The TH400 will require a different slip yoke, and you will need to verify proper driveshaft length/slipyoke engagement into the trans
 

565bbchevy

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Aug 8, 2011
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Unless you are going to source a 350 trans I would go with the 700r4 since it would be only a little more work than swapping in a 400 plus the low first gear will help you get moving if you have your stock rear gear and you also have the benefit of not revving the engine really high if you go on the freeway.
And most aftermarket 168 tooth flexplates are dual bolt pattern and can be purchased for $30 from Summit Racing for non SFI versions
 
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