This engine and transmission are going into a '55 sedan.
The engine is sidemounted. I'm using the pickup cast iron bellhousing.
It sounds like it may be a bit of oveverkill, but since I have both the pickup crossmember with the bellhousing mounts and the Firebird crossmember with the rear transmission mount, I might as well install both of them.
I havn't assembled the clutch yet (I have the bellhousing and transmission bolted to a spare block as a mockup to get the mounts aligned) but it looks like the Firebird clutch and pressure plate will fit the 250 flywheel.