need help ASAP

HI
ok so when i got my 67 cuda the guy told me that it was a 340 crate.. and that was it..

well i broke 3 rocker arms and i need to get some more and i dont know what to rder.. i found these on mopartsracing.com and i called but they said that theres differnt types and idk if i have magnum heads or what or its just LA maybe.. im not sure theses r the ones i was looking at.. they look like what i have on the car now too.. its 144.50 and its under Rocker Arm Packages

http://www.mopartsracing.com/parts/a.html


Hydraulic Rocker Arm Packages

features thicker cross-sectional material in pushrod socket area for added durability. includes 16 heavy duty hydraulic rocker arms, includes rocker shaft retainers, and hold down bolts. Rocker shafts NOT included.
P4529742 "A" engine, standard heads, hydraulic, 1.5 ratio 142.50
service hydraulic rockers

i think these r what i need..

thanks