Group Buy RFC: 18725643 firing order BB roller cam cores

After some research and a few nudges (thank you HardcoreB!) towards using the 18725643 firing order on my next 511. I was thinking that perhaps I am not the only guy thinking about this upgrade (if it really is one) and that maybe we could get a deal on say 10 cores. If there is interest I will pursue the matter further.

Please feel free to disseminate any info you have on firing order swaps. At the "going rate" it is "only" $550 more, or about 2x the price of a custom solid roller. I was kind of against it based on sticker shock but then the little racer buddy on my shoulder reminded me of the other items that cost 2x parts that would have worked "just fine".

My reasoning for trying this is to reduce crank flex and to better distribute the load across the bearings.

Thanks for looking!

if you’re looking to have a run of cores made, you should check with whoever is making them, as I would assume they will likely want them all to be the same...... to be able to get a price break on them.

There isn’t a whole lot of latitude on how much you can change what the basic core is made like, for your finished product.
It’s not as simple as a “firing order swap”.

If one guy wants a .425 lift 114 lsa cam, and another guy wants a .470 lift 110lsa cam..... that’s two different cores.

One core vs 10 cores....... what’s the price difference?

Maybe I haven't searched in the right places, but I haven't found consistent or conclusive benefits documented from firing order changes. It seems to fall under the "it depends" category...

That makes good sense. I wasn't 100% sure where the setup time was spend for tooling up an operation like that. I'd rather sound like an idiot here it's you folks are more forgiving : D

For that price, I would think you could get a tool steel billet. The “core” would be the same, as it is just a round chunk of steel.

They come rough but not a big round piece of steel. The LS firing order is specific to the cam core.

semi finished cam core:

This is what most cam grinders start out with...... which they buy from a core manufacturer like Engine Power or Camshaft Machine Co.

If you want something that won’t fit on an available core, and they have to make it as a one off from a piece of bar stock...... it’s going to be expensive...... and a little time consuming.
First, they make the core...... then they send it out for heat treating....... then when it comes back they rough in the profile..... then finish the profile.
Not all can grinders have the equipment to build the core from scratch, in which case they will have to have it done by one of the core manufacturers........ then have it shipped in for them to put their profile onto it.

Tool steel cam starts as raw bar. Completely cnc machined start to finish, no heat treat. Usually done for higher end builds with unusual needs.

A single odd ball cam out of tool steel would likely be cheaper than a single custom heat treated core. Maybe a 10 count would lower the price of the heat treat core.

Sounds like something that would be way more $$$ than what the OP is asking about.

With an even smaller number of places able to supply them.

What’s a tool steel cam cost?

I was given a range of 1100-1500 for a low deck Dodge early hemi roller. Most of the bigger race cam companies can do them.

I agree, A roller cam core effectively starts out as a raw solid round bar anyway in most cases I believe..

And the cam core for the OP's stated reasoning, he should research further and understand some have chosen one additional firing order swap, (2/3 swap), which is the direction I am going, and doesn't coast a dollar more on the custom cam.

The question is...what firing order would you use?

My intention is to use do the 2/3 & 4/7 swap. I just had to use the LS firing order for this post.

If none of the core suppliers offer that as a normal semi finished core....... then it’s likely going to cost $850+ to get what you want.

Follow-up...
1. Read this: https://www.enginelabs.com/engine-tech/engine/firing-order-swaps-whats-best-for-your-engine/
2. Save your $$$

Great info.

I can't do any back to back but my current engine has a 4-7 swap and it is the smoothest running engine I have had. Comp suggested the swap because it was easier on the rear most crank journal and it moves the hot spot of two neighboring cylinders firing closer to the water exit.

VERY enlightening. Thank You for posting that link.

Not saying that you won't see ANY benefits. However, for the cost estimates being mentioned above, it doesn't sound like a good "bang for the buck" for the caliber of engines most of us on here build.

I'm as guilty as anyone at spending money on the wrong things.

I don't know that we would have paid extra for it but comp didn't charge any extra on top of the custom grind.

I'm a$$uming you're not talking about a generic BB Mopar...

Why would a core for these cost any more than any other billet core, they’re all just a round bar of steel !!!

I'll take a w.a.g. here (and am fully expecting to be corrected by others in the know)...
- Common steel roller cams are ground on less expensive rough-ground cores which are limited as to both LSA and firing order options
- Stepping up to something completely custom will incur a price increase for a higher quality core, as well as additional labor for machining a UGL (unground lobe) core

The cost for a "basic" roller from someone one like COMP is maybe $400; get something from Jones Cams that could be basically the same thing on a higher quality rough-ground core and you're over $500. Go the next step to go "full custom" on firing order, etc., where you have to start with a UGL... all I can presume is it's "more", but don't know how much "more".

Nope, generic LA small block.

To any many times guys get caught up in "zoomy" ideas and parts. I think about ET/$. This does not fit that category in my book. Even though my cam is a 4/7 swap.
Doug

Doug you know I highly respect your opinion so thanks for weighing in. I am trying to factor in a 3rd metric and that is service life. I know how much hp I need to get where we want to be at race weight in blackie.

For laughs let's say it was a no cost upgrade. Would everyone be jumping on the ship?

All input much appreciated!

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It seems like the 700-1100 range is what the quotes are coming back at for a finished product.

For a BBC shelf roller cam, it’s about a $50-60 bump in price.
Comp 11-734-9 vs 11-749-14
Same cam, std FO vs 4/7 swap

(Actually..... those two are only about $30 apart from Summit)

Still not used in everything.

1. I see what you are saying. I have a hard time making decisions based on a few broad, ambiguous statements made by one guy at one company. Especially after being interpreted by another human being into print lol.

2. It's a matter of having lunch at a diner or eating trail mix for a few months. To me there is no savings only allocation.

3. I like the numbered q&a format : D

Get a definitive answer!!!

Buy and test both the std FO and the LS FO.

Then we’ll all know exactly what it did in your particular combo.

Don't think I haven't considered that! The other 511 has a standard FO jones roller so i sorta already have the "a" cam. That one is 112 LSA and this one will be 114 and more nitrous centric build. Both 511's will be 250-300 shot max. Low use stuff as I am just a casual/fair weather car guy lol.

From what I have gathered the only theory behind the swap is cooling and crank whip mitigation. How much is apparently highly debatable.

Are 4/7 swap roller cores available for BBM? Or is any firing order change stepping into $$$ territory?

And, no, I'm not considering this for myself. Strictly "for informational purposes only."

"Asking for a friend"

My understanding is that any firing order change is a custom core. I called a semi local cam.grinder today and the fellow i spoke with did not think it was a big deal to get a core with the 2-3/4-7 swap. It will be interesting to see what he comes up with.

Stop the presses, a critical thinker.

Not me, bro... I ain't got no friends.

I'm sure there are some combinations that would see on-track improvements from firing order changes, once dialed in.

I'm equally sure mine isn't one of them.

Not having a tv does that to ya! I try to make moves based on facts and data. When that isn't possbile you have to take a leap of faith. Lets see...4$ coffee and a Netflix subscription or a custom cam? Much like the government I am guilty of cutting funding to underutilised/obsolete programs and reallocating said funds to tangible goods that burn c12 and make lots of noise. : D. My wife is on board with the "just make a decision and shut up about it" school of thought. She is the only one around to talk to about this stuff lol. Three nights of 2-3/4-7 swap talk has her wanting to move on with the build!

It helps to talk about it, to get it out. I understand.

You called be "bro", like it not we are buddies lol. Think of all the fun things we could do if you had not have run away from home!

I am looking at this from three sides performance x $$$$ x service life.

It's an exercise and to be honest I expected the response to be in favor of doing what we know with the standard FO. It's not like I am trying to revive a set of Stage 6 heads or hotrodding a 276 Desoto. Just pounding out the merits of a FO swap.

From my perspective Andy and PRHman have valid data. Andy dyno'd againt this theory and PRH has marine apps with roots blowers showing zero improvement. To me that is credible.

While articles are good food for thought I don't rely on journalism to shape my future as I don't rely on politicians to have my best inteeert in mind.

It is winter...for you guys lol. I drove my 66 Coronet to town yesterday.

To clarify, I never said anything about any improvements or otherwise with the blown marine builds.
I simply stated that the ones we do, don’t have the 4/7 swap, and reliability doesn’t seem to be an issue.

If I had the time & $$$ to test every "What if... ?" that came to mind, I would. Always questions, never enough conclusions.

As most folks here know, its all about the combination. A long time ago when the firing order swaps were new I saw Dick Maskin asked about it. This was close to the time when he built Pro Stock engines. He said when they originally went to it they did not see any power increase. However since they thought it made sense they stuck with it. He said later after they had continued to develop their Pro Stock program they found that if they went back to the stock firing order they lost horsepower. He could not explain it so I certainly won't try.

They've been riding motorcycles here for the last few days. Winter? What winter?

There are tons of things I’d love to have the time and resources to test.
That being said....... FO swap cams would be way way down on my list of things to play with.

If I did try it, it would be on something where I could get a pair of off the shelf cams for the test.
In other words.... BB or SB brand X.
Both cams for less $$$ than the price of the one BBM FO swap cam.
Plus you can sell one of them when you’re done.

Thank you for clarifying that. This would be a good example of why not to trust second hand info. : D

Would you share the top 5 things you would try first? And for fun how long is this list?

Well, for me the top......at least 20......would revolve around head swaps/shoot outs.

Ootb heads vs prepped heads vs ported heads...... brand A vs brand B vs brand C etc.

I think for the first go around it would be stuff for the hot street/street-strip SB stokers.

I’ve never really A-B’d anything on those....... and as part of that series of tests would be a pretty basic TF header combo targeting 600+hp.

I’d also love to do some testing of various ramp speed hyd roller cams, with a variety of different lifters and spring loads.

The length of the list keeps getting longer.
The more stuff you try, the more stuff you wanna try.

If I won the lotto....... I’d def build a really sweet dyno testing man cave where I could putter around with that stuff at my leisure.