Oversized valves?

[Dieselman7.3]

I was looking at the oversized valves rpm sells, does the head need machining or is it just like replacing stock valves? Also what kind of gains come from them?  Thanks

[JMR]

I was looking at the oversized valves rpm sells, does the head need machining or is it just like replacing stock valves? Also what kind of gains come from them?  Thanks

Bore the intake seat to 90% percent of the OS valve OD than blend the throat and bowl area. The boring can be done on a Serdi. You will need a valve job too. Putting an OS valve on the stock seat really does nothing.....you can pick 7CFM 05 sowith the seat boring and the all the cuts  (30, 45 and 60 degrees) are all the same on all 8 intake seats. Nice.
If you use OS exhaust valves bore to 85% of the OS valve OD.
If you can't find anybody to help you let me know. I have a porting business and have done work for people all over the world. I am in Massachusetts which isn't to far from Maine (well....not to far from southern Maine).

[Dieselman7.3]

Thank you for the input.... price of the valves aren't the cheapest thing not sure what the labor cost would be  but for the right gain of hp/torque might be worth it,  and issues with doing just the intake?