Any b6 motor will do also Ford Capri have them, Batman has also put together a sohc crossflow head using the same kit so theres room also for other heads from B series as long as its 1600 and below and not the 1800 head.

I suggest the A14 and A15 block to use the stock B6 pistons which are 78mm and perfect 2mm overbore for those engines which leaves plenty of rebuilds.

Whichever B6 twin cam head you use its doesnt matter as long as you can run 2 exhaust cams! There are many 1.6 making 160hp atw using OBX cams, milling head 2mm!, racing beat headers, sports cat, 45mm webers with Rowland inlet manifold (only 168aud plus 40aud landed!) and ecu to run ignition only or cheap megajolt crankfire ignition. Same mods on a 1.8 Bp yields just 172bhp atw only 12hp more for 200cc extra.

look at the exhaust cam specs compared to inlet
http://www.solomiata.com/cams.html