Actually the 1.8 IS a stroked 1.6. Same exact block, just longer. Interesting history of the BP series blocks through Mazda.
The 1.9L is actually a Ford designed motor, using Mazda 4cyl specs. However, because the 1.6L was a SOHC its ported just like the 1.9L and hence the EXP turbo Exhaust manifold will work
see what ya learn on here.
Talking about making a stoker...my friend Rob had an 8sec chevelle...the company that did his crank said they would make a crank, and custom notched pistons (on the back to clear the crank). They said it would cost about 6k and recommended using crower rods. But still a balanced crank that could support a rev to like 10k and getting up to a 4" stroke.
I did some quick math when I was at Rob´s house...we figured we could hit anywhere from 2.5-3.0L with the BP8 motor. So the project for the rest of my life looks like its going to be:
ported, polished head, with heavy exhaust lobed cams, cam gears, oversized valves, sodium valves, titanium springs, custom pistons, rods, and crank --- 3.0L running 2BAR of boost on an 8.2-8.5:1 motor reving to 9.5k ..... low estimates can go as high as 500HP.
Just my dream....too bad the drivetrain would never support it....it would be a blast in a Miata though.