The car is originally from California. However I believe they had extra emission regulations to pass? I figured a lot of the extra stuff this car has (such as possibly the valve reliefs) were an attempt to lower them or something.
Thanks for the replies, unsure on the Cam, shall have to check tomorrow on what size lobes it has. I've attached pictures of the pistons, they have AMPCO stamped on the inside so by your attached link I would have thought they are original.. Hopefully its the standard cam in there, it certainly didn't look like anyone has been in the engine since it was manufactured. Although I'm bit of a noob at this so I could be wrong.
New to the site, I've done a lot of Google but can't find the answer I'm looking for anywhere.
Basically I'm rebuilding a california 1973 datsun 240z it has a e88 and p30. As far as I'm aware it hasn't been rebuilt.
I purchased some new pistons however these came with no valve reliefs whereas the ones in the engine do have valve reliefs.
I'm guessing that the valve reliefs are there for a reason. Maybe due to the 73s having bigger valves? (If I read correctly).
I was effectively wondering if there's any chance I could run without valve reliefs. Quite expensive getting hold of new pistons here in the UK so thought I'd ask whoever unlikely