are older jdm b16a camrails different from newer b16's?

i noticed the little holes on the rail that you use to lock the cams are different on my b16 than they are on another b16 i saw.

-older jdm b16


-newer usdm b16


im also curious about how you'd lock the cams on the older b16 heads. is it the same concept as the newer heads?

 

Yes, they are different. newer cams cannot use the old holes for timing.

 

The older ones are also cast aluminum vs billet on the newer engines.