anyone know why indy used the 2.100 in. and 1.650 ex valve sizes? i'm more concerned about the odd 1.650 exhaust valve. why would they use that size when everyone else seems to use 1.60. whats the benefit with that large exhaust valve? seems like they would of had something like 2.08/1.60 as ryan once told me the 2.08 worked better than the 2.100 for some reason. anyway, just curious to what anyone knows about indys odd valve choices.

any cylinder head guru's out there have any opinions on why indy uses the 1.650ex valve while most others are using the 1.60?

The 1.65 is carry over from Batton w2. ( all an Indy head is old Batton stuff)

I run 1.60 in that head then Run 2.125-2.15" intake valve.

that looks like a better valve size ratio than what indy offers. what compression are you at with that valve size?

I had 2.15/1.60 in my 245s.

did you buy them new with those valves in them?

Yes I got them from shadydell that way.

ok, not sure the 1.650 valve hurts anything. I was just wondering why they choose that size. if I wanted a 1.60 valve, would it be possible to go down in size?

Call Indy and talk to Josh. I am pretty sure you can buy them in any form, since they make them from start to finish. So, if you want them with no seats or unfinished seats you could get them that way, but check with them first.

Rod