Alternatively convert the B23 to turbo. 0.040" oversize B23FT pistons, new high volume oil pump, drill the return hole and you're all good. Plug the k-jet holes, bolt on a later inlet manifold (or make your own) and turbo exhaust, chuck on an aftermarket ecu and you're there.
The B23 has the luxury of no harmonic balancer, so you can easily bolt onto the front of the engine like this: http://www.retroturbo.com/?product=volvo-b21-b23-b200-b230-trigger-wheel-kit.
You will never break a B23 crankshaft and the B23 rods are rock solid.