Stove bolt engines as well as other Chevy engines used in trucks and heavy industrial applications used rotating valve spring retainers on the exhaust valves to increase the life of the valve. The installed spring height of the valve springs on a stovebolt is the same no mater which retainer is used.
The valve springs listed for all 1962 235&261 engines are the same part # therefore they are the same spring.
Putting thicker i.e. heavier retainers on a performance engine is asking for valve float. In fact the opposite is true. The higher the RPM the less weight you want on top of the valves ergo titanium retainers.
A quick aside, V8 international truck engines used exhaust valve rotators but they were placed under the valve spring. The exhaust springs were shorter than the intake springs to keep the installed height of the springs the same. Hope this helps.
Hot rod Lincoln you wanna weigh in on this?
