Am at the crucial discission stage myself and these are some of the options considered:
1) 1900 Standard - new rings and bearings, valve grind and new standard, hydraulic cam, 32/36 Weber and updated exhaust system. A sound used motor is an option here - just bolt it in.
2) 2.0 litre short block or long block(with 2.0 head) with the rest of the bits as above. This can be achieves at least a couple of ways a) Used 2000 engine ("Discontinued" by OGTS) so get lucky on the used market b) Bore the 1900 block 2mm and fit Chevy Pistons - see this forum. Needs a sound four-speed or Getrag five-speed.
3) Source a 2.2 litre CIH Opel engine or short block - call OGTS
Four-speed becomes marginal - requires Getrag
4) Source a 2.4 litre CIH Opel engine or short block - call OGTS
Requires Getrag five-speed
5) Fit a chevy 60 degree V6 with appropriate gearbox and diff.
-see this forum
6) Fit a Buick/Rover all alloy V8 with gbox and diff
7)Fit a Lexus or NorthStar motor g/box & diff to suit
8) Small block US V8 - Chevy/Ford/Chrysler/AMC/other GM
9) Big block US V8
10) V10 Viper or V16 Allison
Listed in order of expense/power/time to complete (or not) as the case my be.
There is a lot to be said for a near standard 1900/2.0 or 2.2
