72 cutlass 350 with TH400 into a 78 cutlass

[hammer679]

Bought a 78 Cutlass w/o motor and trans in it. Previous owner had put a chevy small block in it. I want to put a 72 Olds 350 rocket and TH400 trans in this car. I've has this motor and trans for a while but couldn't find an affordable early 70's sooo, this is where i'm at. Has anyone done this? The frame motor mount pads for the 72 don't line up with the holes in the frame of the 78. Questions, what lower frame and upper mounts will i need? Will i need to just drill holes? Also will the 78 cross member work with the TH400 trans? What trans mount do i use?
Any and all suggestions will be appreciated.

 

[TURNA]

Use the uppers and lowers from a 78-88 GBody with an Olds 307 in it.

Then cut off the "ears" on the 400 and slip eveything in.

You will need a different Xmember and a kickdown setup

 

[dr78442]

In addition to what turna said. You can use a 200r4 crossmember to support a turbo 400. A 350 or 200 trans use a different crossmember. Being your car is a 78 you will need to install a frame extension on the drivers side to support the new crossmember. 83 and up cars have a frame extension from the factory http://www.summitracing.com/parts/sum-770307

Summit Racing SUM-770302 Summit Racing™ Transmission Crossmembers | Summit Racing

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[fleming442]

Can anyone confirm 2nd gen T/A 403 frame pads work? I thought I read that somewhere. Then again, anything is possible; how bad you want it?

 

[TURNA]

Can anyone confirm 2nd gen T/A 403 frame pads work? I thought I read that somewhere. Then again, anything is possible; how bad you want it?

I cant see why they wouldnt.

Since they use the same SBC frame side mount

 

[olds307 and 403]

The T/A mounts sort of work with an Olds V8 in a truck in place of the sbc Clamshell mounts. I had to use spacers to properly meet with the sbc frame mounts with an Olds 350.

 

[hammer679]

Use the uppers and lowers from a 78-88 GBody with an Olds 307 in it.

Then cut off the "ears" on the 400 and slip eveything in.

You will need a different Xmember and a kickdown setup

Thanks for the info. Saves me a lot of trial and error. You sure that the upper motor mounts will bolt up to a 72 block?

 

[hammer679]

In addition to what turna said. You can use a 200r4 crossmember to support a turbo 400. A 350 or 200 trans use a different crossmember. Being your car is a 78 you will need to install a frame extension on the drivers side to support the new crossmember. 83 and up cars have a frame extension from the factory http://www.summitracing.com/parts/sum-770307

Summit Racing SUM-770302 Summit Racing™ Transmission Crossmembers | Summit Racing

Free Shipping - Summit Racing™ Transmission Crossmembers with qualifying orders of $99. Shop Transmission Crossmembers at Summit Racing.

www.summitracing.com

Appreciate the info from you and turna. This is kinda a low budget hot rod so i'll need to shop the salvage yards to hopefully find a good crossmember and now that I think of it will probably need a driveshaft that fits the 400 trans. will I need a new diff yoke too?

 

[TURNA]

blocks r all the same

 

[olds307 and 403]

Yes, you need a 32 spline yoke in place of your current 27 spline yoke for the TH400. All RWD Oldsmobile V8 engine mounts from 73 to 90 are the same, 260 through 455. Before that the 330/350 had different mounts than 400/455 but could be swapped between motors if the matching frame mounts were used. Otherwise the height would be off or they might not line up. I tried putting 70 350 mounts on the 88 frame mounts. The through bolt was off just enough that it would not go in. As said where the mounts go on the engine are in the same spot on a 260 through 455.