Someone is asking about this, says its on the trim tag of his 2 dr ht 1967 (not SS) Impala from Arlington assembly.

I looked in all my resources but cannot locate a L60 engine code?

His tag reads....
L60M35U63

I can't say for sure, but on 1967 Chevelles there was an RPO L90 for an export version low-compression six and L92 was for an export low-compression standard V8. I wonder if it is something like that for your friend's big Chevy?

Normally they offered L30, L35 & L36 as optional V8s on the '67 big cars. They were planning on an L68 (the L36 427 with tri-power) but it was cancelled before production. The L72 (427 425-horse) was supposedly not offered but a few may have slipped through. The cops even may have been able to order an L71 (solid lifter 427 tri-power 435-horse).

I was thinking along those lines but he says the car was never out of the US to his knowledge. He found the car in the southern part of US (Texas), maybe it went to Mexico or South and someone brought it back into the US or it was a COPO (Fleet purchase etc like gov't.).

Also the L90 and L92 do show in all my RPO lists (GM ones) but no L60??

I am waiting for him to send me a image to be sure he is reading it correct. I thought maybe he had L30 but he insists its L60??

I wonder if it could be L61 for the 230 cu in 6cyl