Hi,
I have the following questions for the engine guys
My engine: 1977 350 2bbl, 74cc combustion chambers, dish pistons. (Engine is in a '67 cutlass)
1.) Are all 68-77 350 cranks the same? or will interchange?
Yes. The only difference is that engines originally bolted to manual transmissions have the recess for the pilot bearing drilled. Most that came with automatics do not have it drilled. Also, every single small block Olds (260, 307, 330, 350, 403) use exactly the same stroke. Except for the balancing (and the crank flange bolt pattern on the 64-67 motors), the cranks interchange.
2.) Will earlier 350 (i.e. higher compression) heads work on the later block?
Yes, though you need to calculate the real compression ratio based on piston dish, head volume, and gasket compressed thickness.
3.) If the heads work do I need to change the intake?
It's not mandatory but desirable.
4.) Are there pistons available to boost comp to 9-9.5:1 using the 74 cc heads?
See answer to #2. You can get flat top pistons, 6 cc dish, and larger dish pistons.
5.) For dual exhaust do I need both manifolds or just passenger side?
Neither. Olds never made "dual exhaust" manifolds for the small block. All small blocks used the same manifolds. When dual exhaust was used, there was a factory cap on the second opening on the RH manifold.
There is now an aftermarket vendor selling supposed dual exhaust manifolds for the small block Olds, but I got a chance to inspect them at Carlisle and they don't look like they flow any better than stock, so it's not clear they're worth the money.