Vortec valve seats?

[Vikingdude]

My understanding is that SOME but not all 906 vortec heads recieved an inconel valve seat. All of the heads with the inconel seat were single angle only. These came in 1 tons, and lpg trucks.

Don't take this as gospel, I've been wrong before, and I'll be wrong again.

 

[Erik the Awful]

I'd heard that GM was concerned about the induction hardening for the heavier duty trucks and so they put inconel valve seats in those engines. The inconels then had problems with falling out and trashing the cylinder while the induction hardened seats had problems with cracking. Vortec heads are the best factory heads right up until they aren't.

 

[HotWheelsBurban]

Cost cutting, extra time, extra machining, extra parts to do seats. In my experience it was the over 8600 gvwr that got the hardened exhaust seats, early model USA production as opposed to Mexico produced engines and heads.

So that said, sounds like Rawhide would have these heads but the Burb wouldn't (since it was built in Silao, Mexico). The crew cab was built in Flint, Michigan.

 

[Schurkey]

Probably does not matter where it was built.

I'd expect the difference to be in the GVW rating.

 

[Pinger]

I asked on an LPG (propane) forum if cast iron seats were compatible with LPG and was told no, and given the BL A-Series engine with seats cut directly into cast iron that wasn't even suitable for unleaded gasoline - which is true - as an example.
Yet, a GM brochure/PDF for Vortecs for operation on LPG and CNG makes no mention of having any special valve seat provision for LPG and/or CNG running.

 

[Schurkey]

All GM exhaust valve seats have either been induction-hardened (common) or hardened inserts (not common) since the early 1970s.

The L29 Vortec heads I had on my boat for awhile had inserts in both the intake and exhaust sides.