Competition Larger Valves

[dzlpwr]

Does anyone know what valves they are using in the 12v heads to replace the smaller exhaust valve with a larger one? From the looks of it they are just installing an intake valve in place of the exhaust valve and machining the seat larger. If thats the case is there a better intake valve available from cummins for doing this or are the stock ones just fine to use? I would appreciate any feedback.

 

[thekidfan]

Yes, the PDR stage 3 heads have same size intake and ex. valves but not positive if they are the same valves! I would think the intake valves would be fine as they see the same conditions, but not sure if your talking about better valves for both intake and ex. !

 

[F8LDOSE]

I used 1. 77" on the intake and ex. Thats stock size on intake, just a tad bigger on ex. Thats the biggest that will work properly. Obviously you can't use the same valve for both... . Ex. much higher heat. Ferrea made mine from what the call their "special alloy" about $80 a peice. Nothing off the shelf. For under 800hp, it's a waste of money, stay stock size.

 

[Jim Fulmer]

Does anyone know what valves they are using in the 12v heads to replace the smaller exhaust valve with a larger one? From the looks of it they are just installing an intake valve in place of the exhaust valve and machining the seat larger. If thats the case is there a better intake valve available from cummins for doing this or are the stock ones just fine to use? I would appreciate any feedback.

Over rated, don't waste your time or money! The head will never flow enough to really matter.



Jim