99z28ls

what is the biggest exhaust valve that can be used in a 5.3 head while still using the stock valve seat?

omc8

iTrader: (7)

What heads are we talking about here old 5.3 862 or 706s. 2.02 on I and 1.57 on E. I think I would only go 2" on the I and go 1.57 on the E . You will probably want to unshroud the values too.

99z28ls

sorry 862 and they will be on a ls1

99z28ls

bump!

batboy

iTrader: (6)

Stock exhaust valve seat? Then the answer is 1.55". If you mean the largest that can be machined to fit, then 1.575". You might be able to squeeze something bigger in, but that's probably the largest "practical" size exhaust valve.

omc8

iTrader: (7)

Those old 862s only have 1.89 intakes ,I would take them to 2" .Why are you wanting to use these heads, for the compression bump ? Have they been ported?