daniel, exactly right about the ports!!!
The A18 would have to be boosted just like the poor flow of the naps Z18 engine. The pollution head design of the naps engine did well with boost for George Fury.
Id love to get a spacer plate made up if I was still going A series. But I recently bought over ebay a 12v engine from the UK that will hopefully solve all my capacity and fitment issues. The engine is all alloy pressure die cast block and head with different sized inlet valves. Inlets are 36.3mm one, the other 30.3mm with one 40.5mm exhaust. The valve angles of this engine are the magical 16 or 18 degrees. although a 2.2 litre engine 90mm bores instead of 88 can give me 2.3 litres. The best thing is that this engine with a renault fuego compact waterpump makes it 1 cm longer than an a15 and the low height design head makes it 5cm taller. It can drop almost cm lower on the datsun 1000 crossmember by using a dry sump setup. Ill post up some pics of the same engine with the earlier taller 8v head to show everyone why I chose this engine to be perfect. At 4Okg lighter than an sand cast alloy sr20de both fully dressed it was made for the b10. The block is 231mm tall which is 4cm taller than an L20b but the head is so short and the length is so much shorter than an L series that it freaks me out how much better wet sleeve blocks are when they are pressure die cast.
For a nice article on engine masters...enjoy the read...
http://popularhotrodding.com/tech/0603phr_emc/index.html