"could you list or describe the 3 styles of 54-62 valve covers that Chevrolet used?? Are you including the two Corvette covers in those three?"" . . can a 1955 2nd series 6 cyl have a vented vale cover . . "Nope, no need to mention Corvette 235 covers in trying to distinguish different 4-bolt covers - I was referring to high-pressure truck engine covers - the ones with four side bolts/screws.
In my table, I refer to them as "Third Generation Stovebolt engines" (other people might distinguish the generations differently).
I assume that 53-55 235 Corvette engines all had the same older-style of
two top-bolt valve covers, with vent slits and non-vented oil filler-cap.
Valve Covers (with 4 side screws/bolts):
1. 54 cars & 54/55st trucks - 4 vent slits in the top, non-vented oil filler-cap in front
2. 55-58 cars & 55nd-1963 trucks - no vent slits in the top, vented oil filler-cap in the front
3. 59-63 cars - no vents in the top and vented oil-filler cap in the middle
I am most likely wrong on cars/trucks being different in 59-63. However, both of my 1960 and 1959 261s both had valve covers with filler in the front. But, they might be "outliers" because they were most likely "special order" engines. They were big truck engines that should have the standard-equipment PCV, but both engines came with no PCV set-up (school bus engine and high-school shop-class engine).
Please correct/clarify any of the above. I will revise the information as necessary
Here is a
photo of Stovebolt valve covers (2 bolt and 4 screw/bolts) from a
lecture on Stovebolt engine characteristics given to the
Puget Sound VCCA chapter by Pre '68 Dave (a while ago).
