351C Head information from Rockatansky

but not all -GA castings were machined into Boss adjustable hardware heads

 

there was an open chamber brother to the 71 Boss head used on the 1972 HO engine,
 it also has adjustable rockers with screw in studs and guide plates like the Boss. both
used single groove valve locks instead of the multi groove that the rest of the Clevelands got

 

some say that Boss replacement heads could be bought over the parst counter for many
years after the 1971 model year production, and that there was a production run to supply
 the parts counter with Boss heads that has a later date code...  could be? 

 

the 2nd pic on this link http://351cleveland.wetpaint.com/page/4V+Cylinder+Head+Spreadsheet

shows where to find the casting date code for the heads. then using the chart 'sorted by date' you
can figure out where your heads stand in the production timeline and whether they're open or
closed chamber, unless they fall between Sarah's 1F2 and Steve's 1M23 dates

 

Boss & HO rockers, notice no locking tab that fits into the pedestal

 

 

point is lots of guys will call any 4V Cleveland a Boss head

myself included until i learned exacty what made a Boss head Boss

 

when you pop a valve cover let's see what it is!

 

wouldn't you trade 80 #'s or whatever it is for several hundred HP?

 

the first time you hammer down a 4V you'll think the 302's are good for golf carts