Investigating further I found this post from 2003:

"The primary purpose is to let an engine rev higher without valve train problems. In a standard OHV configuration, each valve spring must try to control the weight and inertia of the lifter, pushrod, rocker arm, and valve. As RPM's increase, the intertia gets harder to control. One solution is to install stiffer valve springs, but that has its own set of problems. A rev kit adds a second set of springs, which control the weight and inertia of the lifter, removing a large amount of work from the valve springs (and the pushrods, since they no longer have to work so hard to keep the lifter riding on the cam). Since the lifter is one of the heaviest (if not the heaviest) part of the valvetrain, then controlling it with its own spring greatly reduces harmonic vibrations in the valvetrain at high RPM's and lets the engine rev higher."

Cheaper and cheaper;

3D printing metal intake and exhaust manifolds ...

 https://youtu.be/rFhg02wujqs?si=N25Iotlt1tVcCeFM

Quote from: Dumpling on April 13, 2026, 05:12:21 AM

Not clear about foundry costs, but I think this printer is around $40K upfront, but can obviously be used over and over...
.
https://all3dp.com/4/bigreps-new-one-5x-makes-big-parts-faster-easier-plus-introduces-pellet-extrusion/

That prints in PLA and PEEK which are plastics.

Not suitable for things like intake manifolds and such...

"BigRep offers a specialized range of high-performance 3D printing filaments tailored for large-format, industrial applications. Key materials include heat-resistant HI-TEMP/HI-TEMP CF, engineering-grade PRO HT, flexible TPU 98A, soluble BVOH, and high-quality PLX/rPETG/rPLA, all designed for durability and precision.


Key Material Properties & Uses:

HI-TEMP: High-temperature resistant, rigid, and low-warp, suitable for industrial, high-heat applications (up to ~100°C+).
HI-TEMP CF: Carbon fiber-reinforced, offering high stiffness ( flexural modulus) an

Would you consider casting a special request for your last batch?

I like your efi crossram, but would like to use it with a set of "regular" FE heads, Edelbrocks or TFS. Would that be possible?

Coil packs?

Found it....

I have a SOHC piston...