1970 Chevelle Smog Bracket Bolts which are correct
 

Hey guys i have 2 sets of Smog Bracket bolts for the main bracket that holds the large smog pump.

Both long bolts have R-B-W heads

As far as the short ones go which would be correct for a LS6 454 70 Chevelle

One has TR and the other has what looks to be a double sided D or C.
See photo

Re: 1970 Chevelle Smog Bracket Bolts which are correct
 

I have seen both installed but the 'TR' is the most common and I also believe what the AIM manual calls for. However, remember these are supplied by multiple vendors so there is not a right or wrong per se. I have documented way too many cars with multiple variations of various fasteners sometimes even on the same component. Tie rod sleeve adjusters are a good example and often times vary from side to side on the same car.

Re: 1970 Chevelle Smog Bracket Bolts which are correct
 

Thank You Rick
I will put the TR ones on my car and sell the other set.