Port my current M1 single plane or install the RPM Air Gap?

rumblefish360 said
I have never seen or remembered a spreadbore intake for the W2. The W5 is the only W head to have a spreadbore intake and it is almost exactly the same as the LA intake save the relocated bolt holes that are of course, moved out.

All the rest are a square bore.

Here's a NOS W-5 version I have.