Generation IV Internal Engine - LS3 and Manley Valves different height

I had a caddy lifter come apart in my setup a couple of weeks ago, so when I had the heads off to upgrade to Lunati (Morel) lifters. I decided to change my stock valves in my L92 heads to LS3 hollow intake and Manley SS #11621 exhaust valves. To find that all eight of the Manley valves sit .025" lower than my LS3 valves? Has anyone seen or heard of this?

I had a caddy lifter come apart in my setup a couple of weeks ago, so when I had the heads off to upgrade to Lunati (Morel) lifters. I decided to change my stock valves in my L92 heads to LS3 hollow intake and Manley SS #11621 exhaust valves. To find that all eight of the Manley valves sit .025" lower than my LS3 valves? Has anyone seen or heard of this?


If you are talking the LS3 intakes are longer than the Manley (or GM) exh, thats correct. All LS3 intakes are longer than the exh valves to support the different base circle on the factory LS3 cam. :)

Do you have the weight of the SS valve compared to the stock L92?

Factory L92 exhaust valve 91g
Manley SS exhaust valve 94g