1) What parts are interchangeable between a 74 cutlass supreme and a 76 cutlass? (suspension, rear, etc.)

2) Will a '68-'70 Rocket 350 block fit in a 76 cutlass?

3) Will a chevy 350 tranny fit in a 76 cutlass?

Thanks

 

The chassis are the same so all of the running gear will work. Control arms (front and rear), rear axle, brakes (front and rear) sway bars (front and rear), crossmember (but you may need to drill holes on the frame for the 74 crossmember)
Turbo 350 block? Not sure what you're talking about here. A turbo 350 transmission? That will work.
Chevy trans will not work behind and Olds engine. The only exception to this is if the bellhousing is a dual pattern and those are easy to spot because they have 10 mounting holes instead of 6.

 

Hey thanks. Turbo 350 block sorry i meant '68 - '70 Rocket 350 block lol.

And actually i have a chevy 350 tranny behind this same block right now I just had to buy a trans-dapt plate to line up the holes.

 

Then it will fit in the car just fine. You issue is going to be getting the speedo reading correctly.