What about the pressure plate and harmonic balancer pulley as well as replacing the water pump with a forward rotating water pump in place of the serpentine one?
Are you converting the Vortec to a carburetor? If so, you should be able to use the old style balancer, but you will need to use an old style timing cover as well for the right timing marks. You can't use the 400 balancer or flywheel because the 400 is externally balanced by the balancer and the flywheel. The 350 is internally balanced.
The water pump and pulley setup from the 400 should work fine. You will need a flywheel for a 1 piece rear seal engine because the flange and bolt pattern is smaller for the Vortec engine. Your old flywheel won't fit. Also, you will need an electric fuel pump since the Vortec cam does not have an eccentric to operate a mechanical pump and the block is not machined to accept one.
The Vortec is a standard small block once you strip off all the electronics and fuel injection parts. You will need a Vortec style intake manifold for a carb. The short block is basically the same from the mid 1980's and up, so you will need the parts from this era to complete the swap.
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