Neil Hickman

seems like this is mostly a classic mopar site, but here it goes:

I am rebuilding the heads on my 2003 Durango which has the 4.7.
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I ordered a new set of valves for it and they arrived today. The intake valves look the same.
However, the exhaust valves are different on the face...and I wonder if anybody knows why this is? and more importantly, if they are interchangeable,......

The original exhaust valves are cupped, like the original AND new intake valves.
The new exhaust valves have a FLAT surface, with a small round indent.

I dont have time to order another set, I need to get our family vehicle back up and going....I will use the old exhaust valves if I have to, but then I will raise hell with the vendor.

Any input would be appreciated!!
Here is a picture of the two...the original is the cupped one, the new one is the flat one. Either way Id expect the compression to change..not sure that dimple equals the volume of the cup although I could check it with some water.

Iowan

The compression difference will be minimal, only a few cc and not a concern.

Neil Hickman

I agree, Im leaning towards using them....still I wonder what the difference is.....

Maybe the HO version of the 4.7......

RacerHog

It's just a different MFG of the Valve.... As long as the valve spec is the same your good to go. as in using them.

Neil Hickman

I talked to my Brother who is a mechanic, he said the flat valve is an improvement, since the tulip design tended to pull out of shape on those engines over time to the point where they would not seal and the stem height would get too high which would cause misfires and eventually throw the rocker or drop the valve.

Thanks guys!!