First I let me thank anyone who responds in advance, I am chasing my tail, I thought I has some things figured out and turns out perhaps not.

I have a fresh 408 short block sitting in the garage looking for a home. I also have some bare RHS LAX heads.

Awhile back I picked up some 8mm stem 1.92 intake and 1.62 exhaust valves.

My understanding those are the valves the heads are set up for?

The head is a hybrid of the the LA style head and the Magnum head?

I have a complete XE268 Cam kit with springs 901, retainers, seals, locks etc but it all says it for 3/8 valves.

Seems like the timing set, cam and lifters are the only things I am going to be able to use from the cam kit.

I have a set of 596 heads that I can use the rest on for a 360 in another car.

The local shops are not being very helpful as it's a chevy shop and they seem to be confused about what to run I lost all confidence when they ask if the head was for "a big block or a small block", I've called indy as RHS no longer deals with the head and all I could get from indy was "send em to me I'll set em up right." which would be great but the shipping would be murder.

The obvious solution is to run the springs,retainers,locks and seals for 5/16 valves as that is the same as 8mm correct? I am wondering if I am missing something or just over thinking it?

What valvetrain are any of you running on theses lax heads? The cam specs are pretty mild for a 408 but it going in a daily driver that's heavy 3800lbs. 224/230 @.50 and .477/.480 lift on a 110 centerline.

Thanks for taking the time to read this post.

 

Those heads are kind of a mixed bag of nuts.. However. If your only going to run a single spring, you might be in ok shape? your not going to using a lot of lift. So you could be in the safe margins?
I say Mock it up and see how it turns out... As long as fit the block for oiling and you dont bind it up. I think you will be safe....
Just my 2 cents