Not Ranked
These heads aren't identical, and that doesn't surprise me. What does is which heads have what features. The 352 heads have larger intake port openings at the intake manifold face, larger exhaust ports under the seats, and a lower but more radiused short turn in the intake ports. These look like the better choice for a 390 if big-valved and ported. Right now, both sets have the same valve sizes.
These 352 heads are marked 6090A C1AE, while the 390s are simply C6AEU.
The intake manifold shows 1L17 and C2AE 9425C
So I want the 390, or maybe add a T76 to the 352
|