[steve25]

Let’s get some things / details nailed down here.

The 041 cam has .469” lift with the standard 1.5 rocker ratio.

The RA4 cam as used in the 400 cid motors used 1.65 rockers for a lift of .515”.

With either rockers your stock length valves can be set up by a machine shop to work as long as the proper valve springs are used.

This is a good way to go because you may not need custom length push rods.

The stock valve length in your 7K3 heads is 4.980”
RA4 valves are 5.250” in lenght.

The high comp D port head valve length is about 5.095” and is a good choice to move up to because it will open up the door to more valve springs that will work with .515” valve lift, but custom push rods might be needed .

Other things to note.

1) rA4 intake valves are Tuliped on the back side and in a running motor flow less in a D port head like your 7K3 heads than a stock nail head valve does in your heads.

2) to run 1.65 rockers and .515” lift you need to check if the top side of the push rod holes need to layed back towards the rocker studs so that the push rods do not rub.
If you run only 1,5 rockers this will be unnecessary.

3) the spring pockets in your 7k3 heads can be safely cut .060” to assist in running a taller spring.

4) 455 motors with stock D port heads love .515” lift or more!