Modifying secondary metering rods

[Pav8427]

Good morning gentlemen. I have some time and a fairly good selection of secondary metering rods and would like to make some custom ones for possible future use.
No real application right now, just wanting to make a few sets that may save some time in the future.
I would like to get some input on what cores to start with and a decent range of modifications to shoot for.
These would at some point be used for street performance on mostly mild builds. I would be shooting for a range to get in the ball park when tuning knowing fully that I still may have to make/modify a another set to fine tune.
Would it be a good idea to emulate the AX,CE rods only with a bit smaller/larger tips?
Right now in front of me I have CH,DP,CV and CZ cores. But have many more still in carbs.
Is there another recommended core to start with that I should start with?

Thank you. Doug

[Pav8427]

Anyone with any input?

Thanks. Doug

[Cadman-iac]

  I think GM made a very good selection of rods, if you go through the list at the back of Cliff's book you can see the progression from small to large, (going from memory here).
 So unless you have unlimited time and a lack of funds, then I guess it's worth a try. You probably will have to start with an original rod and modify it, unless you have stock to make new ones from.
 But honestly, if you need a specific rod, call Cliff, save yourself some time and headache.
 Just my opinion.

[Kenth]

I have used a shop with a CNC lathe to copy unwanted rods to CE and AX.
They scanned the original CE and AX rods to have them copied.
If I had needed longer tips on them they could program the lathe for this.
To select suitable rods for the modification I used a sec. rod chart like this:

https://www.thirdgen.org/rods/

[Pav8427]

Definatly not trying to build a better mouse trap that what Cliff has.
Just have some time and access to a mini CNC lathe and a bunch of cores to play with.
I have been a machinist a long time, but havent played with this small of parts.
The more I look at the specs in Cliffs book, the more I learn.
Thought a pile of custom ones layin around would help get someone local out of a bind if they are on a time crunch and want to race or rip up the street.

[Cadman-iac]

  That makes sense, I can see taking a fat emissions rod and cutting it down to make something more useful out of it.
 Looking at the chart of rods, there's not much room left for improvement.  Making a custom rod and trying to figure out if you have dialed it in would be extremely difficult though without the use of a dyno or a 1/4 mile of track.
 The secondary rods have a limited usefulness in daily driving, unless you have all 10 toes located in the engine bay.
 But I'm looking at it from my point of view, regular driving, I don't race, so I don't see a need for a custom rod.
 If you race, I'm sure your point of view is much different.
 I understand wanting to use your C&C machine, I had access to a mini mill for a while and it was fun using it to modify a carb base. I took one that had the enclosed idle screws and cut that part back to expose the screws and make it easier to adjust them.
 Good luck with your project, I hope you are successful.

 Rick