CORRECT POWER BRAKE CHECK VALVE
 

WHAT ONE OF THESE ARE ASSAMBLY LINE CORRECT FOR 68-70 https://www.yenko.net/ubbthreads/pics...9-dscn4317.jpg

Re: CORRECT POWER BRAKE CHECK VALVE
 

I think neither one of those, the one on the left IMO is for mid 70's form looking in junk yards.
This is the one you want.
https://www.yenko.net/ubbthreads/pics...correct_69.jpg
These are later version, close but no cigar
https://www.yenko.net/ubbthreads/pics...-35351-001.jpg

Re: CORRECT POWER BRAKE CHECK VALVE
 

Mike is correct. His picture is of an original yours is later

Re: CORRECT POWER BRAKE CHECK VALVE
 

I see a lot of those on the Chevelle boosters