Correct valve length for an 041
 

I’m gathering parts for an upcoming 455 build with 7K3 heads & an 041 RAIV cam, haven’t decided on whose version of the 041 yet. I’ve seen this done a few ways but when starting from scratch what length Ferrea valves should I purchase? They show listings for RAIV valves as well as standard valves in different lengths? I think the springs most folks recommend are the Crower 405 for taller valves but the Crower catalog recommends the 404’s with their 60919 & finally I’m thinking of using chromemoly retainers so should I stick with stock or something else? The machine shop will be replacing the guides & cutting for Vinton seals then setting everything up including seat pressures & coil bind.

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!

Thank you for explaining, I am going to ask the machine shop to make room for 1.65’s since they are already machining the head but plan on running stock factory 1.5’s to start. So then it sounds like I need to source a set of Ferrea valves with an overall length of 5.095 & ask the machine shop to machine the spring pockets as necessary for height & no bind? What about retainers & locks for those valves?

This what needs to be done to the tops of the push rod holes while your heads are at the shop.

The stock retainers may work, but it depends on the springs you get/ need.
It will be best to purchase the recommended retainers to go with the springs.

Get new keepers when you order the other valvetrain items.

Since you’re machining the guides for positive valve seals you will not need the stock splash shields, and in fact they may not even fit the valve springs you end up getting.

Your machine shop should set up the springs for 125 psi on the seat.
If need be that can be dropped down to 118 to 120 on the seat for the exh valves only.

You need to remove more material than the diagram. On the 6X-4 heads I did they still hit halfway down! Paul Spotts has a tool is a drill guide that gives more clearance.
I do agree with the longer D port valve in the heads-what is in my ^x-4 heads.

Your push rods hitting in your case may have been due to the base circle of your cam, but non the less he is not using 6X heads anyway.

Crower 68404 as Crower recommends for their 041 or 68405’s for valve springs? Trying to avoid Comp Cams but if they have a better valve spring I’ll go that way.

You do not know for sure what your installed height will be to be looking at ordering springs.
Let the machine shop do a valve job ( which the heads likely need) and then supply them with a old retainer and keepers so they can get into the ball park of finding out what springs you will need.

X2

I did 3 sets of D'port heads to a much greater degree than that diagram shows the pushrods still rubbed and it wasnt my cam choice..

anyone that tells you that diagram is all thats needed clearly has not done the operation and put it to task..

that diagram is for orientation purposes at best

heads up on the Spotts tool get the hardened one if you want to do more than one set of heads, the soft one will be sketchy on the second head its used on

Guys it’s not my diagram. It’s out of the HO racing build book.

Stock valve length and 68404 springs are hard to beat with a RA 4 cam. Pretty simple combo.

Interesting, two schools of thought, one for longer valves & the other for standard length. Is it a case of either one will get you the desired results just a different approach in building?

A few reasons.
Like I posted a longer valve gives you more springs to choose from, at least at this point in time .

Longer valves and taller springs means you’re not waring out the springs as fast since your only using some of the lift range they can handle.

Longer valves might save you from the machining cost of having to cut the spring seats,.
This is dependent on the springs you end up using.

You can use a longer valve and adjust the height plus or minus .050” with the valve lock, and more yet with different retainers. The negative lock works better than the positive if the rocker arms are close to the retainer. That is another reason you may want the longer valves.

The 68404 springs are good for about .580” lift with stock dimension valves and spring pockets. If you’re going to keep with a hft, it has most those covered with stock length valves without cutting on anything.

I have some engines with longer valves and cut pockets, choosing longer valves depends what the current combo is, and what you think it might need in the future. My TA is set up for .680” lift with 6x heads.

Steve I understand it is the HO diagram(I have all their books and a few catalogs left. Just stating the diagram is incorrect. Summit 2801 cam. Heads cut 0.050. I had already torqued the heads with Butler head gaskets and did not want to burn a set of head gaskets pulling them and grinding more.

If you get a Spotts tool you can see it takes material off almost to the bottom of the head at an angle. Weird deal my original 78 TA 6X-8s I could run stamped 1.65s and no rubbing.

Like Steve said longer vales better spring IH.

A positive about longer valves they will be inherently lighter than heavy stock valves that also have ben known to break

Length of valve and rocker arm type/brand will affect how much the pushrod holes will need to be clearanced.

We used Crane Energizer 1.65 rockers on a bone stock TA 6.6 and one of the pushrods rubbed enough to make an annoying clacking noise.

I think I’ll call Crower to get a better understanding but looking in their catalog they recommend the 68404’s for the 60919 cam except when using 1.65 rockers which I eventually plan on using once I’m through break in. When I look at the specs for the 68405’s they seem to be the right spring with 110lbs open pressure. All this will of course be verified by the machine shop but I’m trying to figure out my parts list since I’d prefer to have everything on hand once the heads go to the machine shop. I think I’ll follow the advice of the longer valves to future proof myself even though I don’t ever see going to a roller cam.

110 lbs is not right with 30* valve on a 60919, or any of the RA4 copies. That number should be 120 to 125 lbs. A seat pressure of 110 lbs is if your heads are converted to 45* intake seats. The stock 30* will bounce and trim off the engines top end power with 110 or less seat pressure. You’re better off with more seat pressure and less spring rate with a 60919 Crower with the stock 30* intake angles, even with big rocker ratios. The Crower has better, smoother more modern ramps than the other RA4 cams (with the exception of the Crane 041 version), and works great with a regular lifter..

Last time I read a 60919 cam card Crower had hydrualic roller springs specs on there. I don’t know what you may dig up if you go looking hard. It depends on who you talk to in the tech department at Crower. You will get a different answer everytime you talk to a different person there.

The last 60919 I did has an Erson dual valve spring for a 1.7 installed height and 120 lbs seat pressure, 325 spring rate IRC, it is close to a Crower 68404 for spring pressures. That cam has 1.65s rockers on it, 96 headed 455, has the stock length ferrea valves, it has around 20k miles on it now,

The main thing that the OP needs to do regardless of the valve length used is to replace his stock however many 10K thousand mile valves with new ones.