<VV> Corvair questions

[Mel Herwald]

I'm a serious lurker. For a long time I have pondered many Corvair related
questions.

Now seems to be a good time to ask some of them. This time I'll concentrate
on heads.

Question #1: I've torn down several dual spring heads. Some intake valves
have T1 stamped on them and some have just a T. What is the difference?

Question #2: There are different thickness and shaped retainers. Was this
due to different vendors or is there some other reason?

Question #3: Why do most intake valves have one groove and most exhaust
valves have 4 grooves? FC valves with rotators may be an exception.

Looking forward to some informative replies. Thank you.

Mel Herwald