do you have Steve Dulcich's hp/tq graph from his 2003 EM 470/Chapman

... My 517 Chapman design was based a lot on what I learned from Steve's 470 motor and discussions with Dyanne and Dan Costello....and it's the flattest/broadest torque and fastest revving wedge I've ever built...by a mile.

After my 2016 EMC build 469 ci SPEC build using RPM heads I have determined some eye opening results. The SPEC rules that year mandated the use of Edelbrocks RPM heads and no welding or epoxy whatsoever was allowed so this limited us to a stock offset rocker. We were also required to use the stem size and head diameter of the valves that Edelbrock states. This meant 2.14/1.81" and that was it. The cylinder heads were ported hastily and a peak of 298-299 cfm was my first and last result--meaning I didn't agonize at all--they were what they were and that is all. I made a best of 592 ft/lbs @ 3500 rpm ZERO dip and 653 ft/lbs @ 4800 rpm with 680 hp @ 6100-6300 rpm IIRC. This build really makes me question the Victors when used with a standard port opening, I mean if you are required to use a big .650" offset rocker then why the heck would you NOT open the port to gain more CSA?

What this means to me is--On your engine Brad, the Victors are a waste. You could have gotten where you are with regular old RPM,s. I've said it before and I'll say it again--I don't know why Edelbrock would even offer them in a standard port. IMO selecting standard port Victors and not targeting BIG power--800-900HP is a dichotomy. Victors should be used only by masochists and those that are hoping for well into the 800+hp range. J.Rob

IMO, if you replaced Brads Victor heads with a set of 300cfm RPM heads, milled for equal compression, and left everything else the same, the motor would have made way less power. I don't think it would be much, but even if it was 40hp less than are the Victors really worth the ROI?

Additionally, in "engine contest" trim, there would certainly be some more power available from that combo.
More aggressive cam, more rigid rocker arms, ported intake manifold, gas ported pistons, lower tension ring pack, 4500 carb on an HVH SS/adapter...... It easily would have made solidly over 700hp. You bring up some good points here but using my 2016 469 I had 1.5 Comp rockers, no spacer, Holley 950 XP 4150, standard tension rings albeit .043" 3mm Total Seal AP's. Had I been allowed to use a spacer then yes I observed 696HP w 1 1/2" Wilson 4 hole, A 4500 would have undoubtedly yielded even more. Again I would ask just how much power are the Victors worth? 40, 50 hp?

When the RPM heads first came out I built a 448 that was very comparable to Brads 452(same cr, similar cam).
I ported the heads to flow in the 300cfm range, and tested them on the motor with a few different intake and carb combos.
At that point, the best intake/carb combo i tried was the Weiand TR with 2 x 650 Demon carbs on it. That made around 595tq and not quite 640hp.
The next closest single carb test was around 625hp, with a similar drop in tq.

Brads Victor combo made 684hp/605tq with an old school HP950 Holley on it(1.375 venturi), which resulted in the motor using 20cfm less air than when the bigger carbs were being run.
Had the bigger carbs been better optimized for the motor, I have to believe some benefit could have been gleaned from that extra 20cfm of air. You know yourself that moving more air but not making power with it is inefficiency. This is telling you that that carb is simply a better fuel mixer. I doubt you could ever turn that extra 20 cfm into power--there no way to trap it without getting into the cam timing events.

With the current crop of std port offerings available, for me the real litmus test would be how much difference in power there would be if you pulled the Victors off Brads motor and plopped a set of ootb TF240's on it.
If it made within 10-15hp of the Victors, then that would be a good argument against the viability of the std port version of those heads, at least at that power level.
It would be a fun test. It would be a cool test and I'm glad you brought up the TF240's. To me there are nothing more than a fully CNC'd RPM with a slightly nicer chamber. I will have an opportunity to work with them soon. Again--I will reiterate, The TF's cannot be any better than an RPM with the stock valve placement and stock rocker offset.

The nuts and bolts of this particular test is that Brad replaced his ported std port Stage 6's and flat tappet cam with the std port Victors and a roller cam and picked up 20ft/lbs and 60hp. I agree but this can easily be attributed to the roller cam swap. I have seen a 50+ gain with my own eyes, same engine/ same dyno 2 days. Also the Stage 6's could have easily been inferior to Victors that you and Brad ported with the knowledge you have gained over the years.

There are a few things I don't really care for in how the Victors are made, but I'd say the biggest "problem" with the std port version for me is the they are cast with the bowls .300 smaller in diameter than they should be.
If they had the bowls sized correctly to begin with(sort of like the original version was), then I would feel better about recommending them for the hot street applications where a high flowing std port head can work. Totally with you on this

As they are now though, they're too labor intensive to be cost effective. Nailed it again

I doubt you could ever turn that extra 20 cfm into power--there no way to trap it without getting into the cam timing events.

Actually I was thinking (and judging from the caliber of respected participants) that this was one of the more interesting threads in the past several months.

Jesse, I guess we look at the Victors through different eyes.
It seems like unless you take them “to the max”, and bolt them onto a similar type of short block, to get every last possible hp out of them, then they aren’t worth using. Agreed

I see them differently.
Again, “if” they had the bowls sized correctly(or using the Pro Comp head)it wouldn’t take any more time for me to port them into the 340cfm range than it would to port an RPM to 300. But they aren't sized correctly so its another check mark in the Con column.

They aren’t that much more money, you get away from the valley pan gasket, and the chambers are better. Chambers are no better. They still make best power @ 35-36 total timing. What makes you say this?
If you bought TF240’s and used the recommended HS rockers for the TF heads, or something like T&D’s......then the cost difference of the rockers is diminished considerably.
Like I said previously, the big hurdle in using them for me is the way the bowls are cast.
One thing I do like about them is they are a true std port head. Not a MW head with a reduced port opening at the flange.
If, in your words, flow is velocity......then at 350cfm from a true std port head.......they should be pretty good.
IMO, if they made 30hp more than a set of CNC RPM heads on the same motor, same cam, same compression.......I’d be fine with that.
I don’t feel like I need to make 800hp out of them to have them be worthwhile. If I can make 700hp from a far cheaper RPM casting then why would I expect the same power from a "better" cyl head?

With regards to Brads combo, there is no way the two cams used in his motor would be 50hp apart......with either set of heads. Maybe 1/2 that.
As for whether or not his stage 6’s could have been improved today......that wasn’t really part of your original argument. You said your 298-299cfm RPM heads would have made the same power as the Victors.I'm saying they could
If that’s the case, then the Stage 6’s would also be just as good, since they flowed a little more than 300, and have a better chamber(although those heads required way more work to be made usable than the Victors). I have no input on the previous Stage 6's. What I was implying is that you would no doubt improve them if you were to use them again.

Also, at 350cfm @.700 Victors have a better discharge coefficient than the RPM’s at 300, or the TF’s at 325(what they flow on my bench).
A 251cc MCH CNC ported RPM flows 315@.700 on my bench.

If the flow doesn’t matter, and the c/d doesn’t make any difference........we might as well stop testing heads, since the numbers must not have any bearing on power output. Never said anything of the sort.

Until someone does “the test”, it’s all just speculation.

It’s easy.......don’t like ‘em? Don’t use ‘em.........plenty of other choices. I won't

As for the carbs.......couldn’t disagree more.
I tried my HP950 on his motor as a point of reference to gauge how well the other carbs were doing their job. It’s by no means my best carb, yet was basically as good as the others we tried.


You totally lost me here.
By that logic I guess I could have put a 650 on it and made the same power with even less flow through the motor. You're putting words in my mouth and jumping to conclusions. I test a lot of DIRT 358's that mandate a 650 and everytime we try a larger carb it doesn't hardly ever yield more power--maybe 5 hp more with a big jump in CFM through the hat-these are on 570-580hp engines too. I look at manifold vacuum closely and see best results when 1.5-1.7 " hg is observed.

I’m confident that had I run the motor with my ported annular 850(which flows about 40cfm more than the HP950) it would have made 8-10 more HP........and picked up most of the lost 20cfm. Dry flow on the bench doesn't mean a whole lot but perhaps you are right-wish you would have tried it.

I’m confident that had I run the motor with my ported annular 850(which flows about 40cfm more than the HP950) it would have made 8-10 more HP........and picked up most of the lost 20cfm. Dry flow on the bench doesn't mean a whole lot but perhaps you are right-wish you would have tried it.

If I can make 700hp from a far cheaper RPM casting then why would I expect the same power from a "better" cyl head?

If the flow doesn’t matter, and the c/d doesn’t make any difference........we might as well stop testing heads, since the numbers must not have any bearing on power output. Never said anything of the sort.

Sorry guys, I was just going by the thread title, I didn't think the discussion was limited to the merits of the Victor, or TF, or Chapmans or whatever...I didn't think anything I was saying or bringing up for consideration would be considered going "off topic"...was I???

Actually I was thinking (and judging from the caliber of respected participants) that this was one of the more interesting threads in the past several months.

Victors should be used only by masochists