Join Date: Sep 2001
Location: North of Philly
This is confusing to me.
Here's my understanding: Standard cooling is what was standard on the car, extra cooling was the "extra cooling" option ($13.) Seems simple enough. Extra cooling was a mandatory option for a/c cars.
What I think is confusing is the placement of the "x" in the '75 MPC for 351(4/B)-w/o 3.5/1 axle ratio (non-a/c) entry, which I'm guessing is a typo.
For 351-4V cars, with no a/c, and 3.25 on down rear end ratios, you should have received the 20" radiator, c9ZZ-8005-E. The x shows this as the extra cooling option, but the '75 edition DOES NOT list a "standard cooling" radiator
The '75 MPC also lists for 351 (2/V, 4/V) with the extra cooling package the D0ZZ-8005-D radiator, which is the 24" radiator. This is also the a/c radiator, automatically added with the select-aire option (A/C.) With 351 (4/B) with 3.5/1 axle ratio, the D0ZZ-8005-D radiator (the same as the a/c radiator) is marked as the standard and optional "extra cooling" radiator (I'm guessing extra cooling was an included/mandatory option with the 3.50 ratio.)(Note that the '75 MPC lists the 24" radiator for both the standard cooling and extra cooling on the Boss 302, extra cooling was an "included option.")
Thus, there was no "standard" radiator for the 351 4/V cars that didn't have 3.50:1 ratios according to the MPC, which makes no sense.
My understanding has always been that the 20" radiator (C9ZZ-E) should be the standard radiator, and the 24" (D0ZZ-D) should be the radiator you received for paying your extra $13. If the extra fin count was the difference, Ford would have had to stock an additional radiator on the production line for just 351 4V cars with 3.25 on down rear axle ratios, which I don't think is likely.
Unfortunately, there is no reprint of the '70 engine assembly manual, so the easy cross-reference isn't there.
As Jeff said, the MPC's aren't exact, my guess is that the first x is one column off in the '75 MPC, otherwise, there is be no listing for cars with standard cooling, and two listings (one a 20", one a 24") for the extra cooling package.
'70 Boss 302
'70 M-Code Vert w/ Shaker
'85 1C SVO
'11 Shelby GT-500
'02 Excursion (7.3l)