Here is a link to back when I did my intake manifold swap:
https://www.honda-acura.net/forums/s...threadid=30051

p.s. Only 3 of the U.S. 4th gen models have the dual-runner intake manifold of the F22A6 engine shown below:

1990
DX - F22A1 Engine, 125hp
LX - F22A1 Engine, 125hp
EX - F22A4 Engine, 130hp

1991
DX - F22A1 Engine, 125hp
LX - F22A1 Engine, 125hp
EX - F22A4 Engine, 130hp

1992
DX - F22A1 Engine, 125hp
LX - F22A1 Engine, 125hp
EX - F22A6 Engine, 140hp

1993
DX - F22A1 Engine, 125hp
LX - F22A1 Engine, 125hp
EX - F22A6 Engine, 140hp
SE - F22A6 Engine, 140hp