I am curious about the differences between the P30 (B16A) and the P73 (B18C/B16B) cylinder heads. I realize they run different valve trains, but what are the differences in the heads themselves. Trying to determine if it would be worth starting with a P73 Head as opposed to the P30 I have. I'm considering a head job including P&P, valve job, and new valve train, and if the end result is the same whether I start with a P30 or P73 head, there's basically no since in me running out and picking up a P73 head.

 

p73 have a MILD factory P&P job and a COMPLETE p73 head has a better intake manifold, cams, valvesprings. you can pick up a p30 head an have a much better P&P job done an get better cams an valvtrain ,which you will need anyways even if you have a p73 head, if you go with more agressive cams. IMO keep the b16 head.

 

The casting for both heads is basically the same. The P73 head has a mild port'n'polish job. Other than that, the only difference that I know of is the differences in the valvetrain that you already mentioned.

 

In addition to the pocket porting done by a Honda tech (no pun intended ) in Japan, the ITR head has a better valve job/throat configuration along with ITR specific vavletrain. Cool thing to is that Mr. Honda felt the need to help racers so Honda prices the ITR heads lower than P30 or P72 heads! Just ask Ber-O, the OE parts guru.