I know there both PR4 head codes but are there any other differences between them. Can you place a B18A head on a B18B block and keep aprox same compression ratio. Are there any problems with piston to valve clearances. Are the cams the same lift/durations or is one gonna be better then another?

 

afaik the heads themselves are identical. differences are in the valvetrain from 1992+ vs 1990-91

 

also the manifolds are different from 90/91 and 92+. The later manifolds flow better.

99+ B20Z cams (stamped P75) are also the same as 92+ LS cams, but have a few more degress of duration on the intake cam.

RJ

 

kewl so seeing I have the B18B cams and intake mani just use throw those in/on the B18A head and its all good

 

Actually, the 1990-1993 (B18A) head has smaller intake ports.

 

hmmm thats strange about the valves b/c went to acuraautomotiveparts.org and they both were listed as the same p/n for 92's and 95 just to throw out some years??? are you sure about the differences in valves??