Power valve recommendations.

[earntaz]

I have a 3878261-EH 3310. Without success I have been trying to find out what primary and secondary power valves were in installed from the factory. The internet has been no help as the numbers are all over the place. Hope I can get some direction from the folks here. Craig

[napa68]

It looks like it is a 6.5 valve Craig..........

https://documents.holley.com/techlibrary_carb_numerical_listing.pdf

[earntaz]

That listing is where I have an issue. The carb I have is and early 4150 with two PVs and it indicates *(12-13)* which does not appear at the end of the chart. The listing on that chart is a single PV for a 4160 carb. UGH! Thanks for the response!

[Steve Shauger]

Do you know the vacuum at idle the engine produces. That will guide you as to # PV needed. I think Tim's 6.5 # will work fine. Call our sponsor Custom Carbs Tom or Phil can help you.
https://customrebuiltcarburetors.com/

[mhm1966]

I agree with Steve that Phil will be able to help you out. I have included Phil's contact information and a Holley Specification Chart.