Its quite a short block design and its the same i saw a year ago on a skyline which really confused the weenies out of me cause the block said ca20 (now in hindsight ca20 and ca18 are related doh!). However this engine had head missing and I could see the valve reliefs for 4 valves on the pistons so it must have been somekind of ca hybrid unless the reliefs are there for some other reason or it was rebuilt at some stage with ca18 twin cam pistons??? .
How crap are ca20 ???? can anything be done to them to make them go like fitting a ca18de internals and head and still keeping the old block number?
I have a similar engine but mine might be a later version. Mine runs the 8 plug head and dizzy with 2 coils. Also looks to have a different rocker cover design. Same Air research M10 turbo though. I have a T25G to go onto mine also.