SBC/Brownfield heads, Why intake valves .100 longer than exhaust?

[RichardSIA]

Trying to get back to my 327 build.
Have a set of Brownfield aluminum heads for it that need a bit of work.
Apparently some guys like to use .100" longer intake valves, why?
This was done to my heads, I need to know if I should replace the intake valves as part of the rebuild.

If it's done for super hi-lift cams I doubt I will need them.
I expect my cam to end up something like an updated "30-30" so only around .485"-.520" lift.

[David Pozzi]

Probably to fit an adequate valve spring in there without coil binding it at full lift. Check what spring diameter the spring seats are cut for

[btmatt]

the roof of the intake port was taller to gain improved flow. This in turn requires the spring pocket to be raised thus requiring longer valves to stay away from spring bind at high lift. The exhaust would probably be longer too to keep from dealing with different length push rods.

I have not seen a pair of those heads in ages, but man they were the thing in the '70s and '80s.