Powertrain rebuild on the 1995 Saab 900 turbo convertible.
A few notes regarding the 2.3 engine swap. It has to be of the same
generation, e.g. for NG900 you need a 2.3 turbo engine from a 1994-1998
9000 (B234E, B234L or B234R).
The head and the block are exactly the same. The timing and balancing gear
is also the same. The end plate is identical. The only internal difference
is the crankshaft with pistons (longer stroke), so you can either find a
good 9000 engine and drop it straight in or rebuild your 2.0 with a
crankshaft/rod/piston combo from a 2.3 turbo. The 2.3 N/A has the same
crankshaft, but weaker pistons.
Further differences: the 9000 uses a different oil pan, timing cover, pumps,
manifolds, mounts and other accessories. You will have to reuse all those
parts from your original engine. The block will have the provisions for all
configurations, but because the accessories are mounted differently, some
bolt holes might be exposed to rust and need their threads refreshed.
The 9000 ECU is reported not to work correctly in NG900. A stock NG900 ECU
will start and run with a 2.3, but it's certainly better if you can source
a custom tune.