BBC Rocker Arms

[ted]

Good morning gentlemen!!
I have tried the Google method(s) on these 2 BBC rocker arms and the responses are kinda all over the place re. the correct dates of SHP usage.
L rockers are good for 1965 - 1969 inclusive engine setups.
H rockers are good for 1970 and up engine setups.
Am I correct or not re. the dates?
Thanks!
Ted

[L72Chevelle]

There were different rocker arms used for different big block applications over the years. Here's the deal:



"no marking" rockers-----these are most likely aftermarket pieces. Most aftermarket are unmarked. However, I believe that they may also be GM #3860305 which were used for 1965-72 non-SHP applications;



"L", "Z", or "X" tip marking----GM #3860308. Used for 1965-69 with SHP and 67-E69 L-88. Also, replaced the 3860305 for SERVICE effective February, 1972;



"M"-----GM #6258611-----used for 1973-74 all big block. Also, became SERVICE for 3860308 effective Novemeber, 1972; currently replaced by GM #10112680



"H"-----GM #3959182---used for L69 L-88, all 1969 ZL-1 and 1971 LS-6. Currently replaced by GM #12368082 which is a kit which includes 1 GM #3959182 rocker + ball and nut.



There was no "N" that I know of; you may be mistaking a "Z" or an "M"