Octane rating

Hey folks - quick question about what octane fuel I should be running. Its an 1988 Mitsubishi L200 - didn't come with an owners manual and wouldn't help anyway as the previous owner replaced the factory 2.6 with a 2.0L 4G63 8V SOHC. I've just replaced the factory carb with a Weber 32/36 and have installed a electric pump to replace the mechanical. So was just wondering what octane fuel is actually best for this engine - have been running NZ 91 in it (which I think is equivalent to US 87?) but realised the label in the gas flap was for the original engine.

Cheers!

Unless it pings there isn't a reason to go higher than US 87, thats what the standard 2.0L calls for

Yup, US 87 octane (RON+MON/2 rating) should be equivalent to NZ 91 (RON rating) -- i.e., regular grade, no need for midgrade or premium unless it's knocking, which it shouldn't be unless maybe the swapped engine was rebuilt with high-compression pistons.

Excellent - thanks so much, will keep using regular in it :)