Seavair

Hi Everyone,

I have a set of 413 RV heads that had a valve job . I was thinking of putting them on the 413 in my imperial, and wondered if they would work. The heads look to be the same overall size. The RV heads have extra water ports which would I think would be blocked by the std head gasket. The valves int he RV head look a little larger, but I am not sure about this . Anyways, I was wondering if this swap will work, and if anyone has experience running RV heads on a std engine

Thanks, I appreciate any input you might offer.

Iowan

What part number is on the head's?

Seavair

the RV heads are 4006452 26 f, the original heads are 2406516-6

Iowan

The original head's are close chamber the rv head's are open chamber so your going to louse .75 or more in compression. That said the rv are better flowing larger valves etc..

Your and most 413s were designed to use the small chamber head's.
Please rebuild the original head's.

Iowan

The biggest thing is, don't give up compression ratio on a bb mopar!

Seavair

I may not understand the difference between closed and open chambers . I attached photos of both heads . They look the same to me. What am i missing?

Iowan

They are a full point less than advertised.

Iowan

Note the difference between the two!

The line across the original head's.

Iowan

If you can't see or feel the definition between the two, I can't help you!

Seavair

I appreciate your help, and i am trying to understand what you are telling me . When you say a line, is this what you mean?

Iowan

I will try one more time, the line across original head's, small chamber.....

RV head's, the chamber is round------ no line...Open chamber = lower compression....

RacerHog

Let me help... The part where your finger is laying across is called the quench pad. The one without the step is an Closed Chamber head.... The other head with the step, is a Open Chamber.
452's are a 2.08/1.74 open chamber head = lower points in compression.
76-78 400/440
@
516's are a 2.08/1.60 closed chamber head = More compression.
64-67 361/383/413/426

And somewhere in there there was a small valve 440 head? I dont remember if it was Open Chamber or Closed Chamber. But I cant remember and I'm to lazy to go look....lol

I would say for what your doing with the car. Jusr rebuild the OEM heads and call it a day. Just my 2 cents. 413's run pretty good. But if your going to hop one up. Do the whole motor and put all the rite parts in it from the get go.

Seavair

Thanks for the explanation, I finally understand the difference.

So i guess i can use the RV heads, but i expect i would be disappointed in the performance

RacerHog

Yes, Unless you build the whole engine for performance.

If your thought is just head swapping, Your more than likely not going to feel much if anything in the seat of your paints.