Two versions, one for 53 and one for 54/55. Both versions used a vette specific head. They are as rare as hen's teeth. Rarer even as Snagglepuss would say. The 53, no holes for the valve cover like the later 54 and 55 version, the 53 motor used the rocker studs. Also, if you look closely at the above photo, you will notice the profile change in the front of the valve cover to accommodate the hood of the Vette. The 53 valve cover is nearly unobtainable. For 54 GM used the 4 screw valve cover. The 54 valve covers used four slots punched into the valve cover itself and a non-venting oil cap. Lots of people think the slotted valve cover is specific to the vette but it was actually used on all 54 235 motors. In 55-58 car and truck line, the valve covers did not have slots but did have a vented oil cap. What I dont know is whether the 55 vette with a 6 used the solid 55-58 style valve cover or the 54 style slotted valve cover. If I was a betting man, I would bet it was the 54 version given the lower profile of the non vented valve cover cap as opposed to teh taller 55-and up vented cap. I have never seen a 55 vette with a 6 in it personally, they are exceedingly rare, I think only 6 or 7 were ever made that way. The air breathers for the YH Carter side drafts are different between 53 and 54/55 and also ungodly rare, as is the ignition cover, cable drive tach and generator for the tach. There are lots of vette specific parts on these three year vette motors that are rare and expensive. Interestingly enough, the intake and exhaust are way easier to come by then the other parts primarily because you could purchase both the split exhaust and side draft intake over the counter at a chevy dealership and many of them were sold over the counter.
The aftermarket also sold triple side draft intakes and they turn up once in a while, not anywhere as expensive as the real deal vette intake but the challenge is always finding the right carbs. Then the challenge is seeing if you have room to install depending on the location of the master or slave cylinders, that sort of thing.
