[GearHead69]

I bought some bare 492 double humps and I'm now looking to buy valves. But every site I go to has 2 different sizes in length, the 4.905 and 4.910 and both say (stock length) They have me confused.. But what should the 3991492's valve length be?? They are stock. Thanks

[superrodder]

Either will work,just use all the same length to keep the spring pressures equal for each valve..005 is not enough to worry about.most chevy heads are assembled to looser installed height variations than that.