I did read this thread, but apparently the original author was mistaken for thinking all ram air heads were round port. The early ram air heads were D port. The #12
s Are D port.
Now what pinion head wrote....well that makes sense, except. ..they did not use #12
s on automatic transmission cars......That's where they used the #13
So, can anyone confirm or deny, did they make any ram air lll car that had a automatic transmission ???? ( firebird or GTO).
I'm having a hard time believing they where all 4 speeds...
heads were used as RA III heads on both the manual
(3-speed & 4-speed cars) with block code WS and the automatic
cars with block code YZ - for the GTO
The early 1968 RA I heads #31
were D-port. The 1968 1/2 RA II #96
were round port. RA III heads for 1969-70 were D-ports and RA IV were round ports.
Looking at the Firebird engines, for 1970, I see heads 12/13 listed as RA III on the 400CI automatic car & #12 for the manual.
The difference between #12 & #13
with regards to the Firebird are unknown to me. It may be that they were used after a specific date post #12 heads. But regards to the GTO, #12 is the correct RA III head.
Just found this from another website: "70-RAIII(d-port) m/t FB's and GTO's used #12's. With a/c #13's. Some auto's w/o a/c got 13's too."
From another Trans-Am site, the #13's were typically for automatic cars, but 12/13 seem to be interchangeable for the F-Body cars only as RA III heads.