Although I don't have them back in my (not currently) greasy hands, yet, I wanted to give y'all a Preview of Coming Attractions re: the standard-port Edelbrock Victors that Dwayne Porter at Porter Racing Heads is completing for me. Pictures will have to wait until then, too.
"Why < you ask > did you have PRH do another set of Victors when you already have the Hughes CNC-ported Victors you bought YEARS ago and still haven't run?"Good question! And one that I've asked myself many, many, (did I mention "many"?), many times.
First... because I'm an IDIOT. This is probably not a surprise to many on here, but I'm willing to be perfectly transparent on this point.
OK, now that we've got that out of the way, I'll touch on the other reasons that inspired me to take this on:
1. I'm stuck on running stock-stroke 440-based combinations. While everyone else is looking for 4.15" or 4.25" cranks to drop into their B / RB blocks, I've been happy reaching a performance level w/ my RB 451 & 452 engines that were slowly approaching the track-legal 10.0 limit for my '73 Challenger, a.k.a. The MoPig.
2. I don't even think of my engine as a stock-stroke 440, as much as a 3.75"-stroke 452 c.i. small-block with a long 6.76" rod and a seriously HEAVY bob weight.
3. The Hughes CNC'd heads, which I will be running when I FINALLY (EVENTUALLY?) get The MoPig running again may, in fact, work great. He11, given the $$$ I've put into them, I should seriously hope so. And if the car steps up its performance from the previous 10.5s at 126+ bests in good weather w/ the old combination to something much closer to 10.0s in comparable conditions, then they'll have proved themselves (along w/ the switch from the old solid flat-tappet cam to a solid roller).
4. However... in terms of port size & runner volume, they're waaaay larger than the old Stage VIs that Porter Racing Heads did for me years ago. Yeah, the Hughes heads are 20-40 CFM better than the Stage VIs depending upon the lift point checked, but they're also 60+ cc larger in volume (even factoring in the Stage VIs were used w/ RB intake spacers and the Victors have an a designed-in port extension that serves the same purpose for a raised-runner head). Cross-section area on the Hughes heads are - in blunt terms - freakin' huge compared to the small-port Stage VIs.
5. Simply put, I think the Hughes heads, even though not their Max Wedge version, are a BIG "standard" port head that might be better suited to an application w/ more cubes than I have. And that concern made me start thinking some time ago that I might want to hedge my bet by coming up w/ a different set of heads based on the premise of keeping the runner volumes and the cross-section areas smaller, thus better suited to my combination.
6. A few "convenient" events that supported this decision:
a) A few years ago Brian at IMM ("ou812") built a 400 motor w/ a set of the later model (has a smaller chamber with more quench area) Victors and sold the short block off after dyno tests only. Those heads, other than having an IMM valve job and some milling for his desired chamber size, were unported... and just sitting on a shelf at IMM gathering dust. So, we talked a few(?) times and I ended up buying them "as is".
b) I saw pics of the CNC chamber that Hughes came up with for the later model Victors and decided that, even though I wasn't interested in their CNC ports on these heads (remember the goal was to have a smaller-volume intake runner, not the same as I already had w/ the earlier heads), that could be a time saver in getting the heads ready. Hughes was willing to do just the chamber portion of their CNC routine, so that's what I had done.
7. My original plan was to do the porting myself, which is why I did an R&D project on a Procomp Victor-clone casting see what I could come up w/ on my own. I sent this head up to Dwayne to check on his flow bench (more powerful than mine) and give him an opportunity to see what he could do on one port vs. my two different hack-job R&D ports. My work wasn't horrible, but Dwayne came up w/ a more effective port across the majority of the lift curve, and did it w/ a smaller final runner volume than my two ports. Hey, it's what he does for a living, so I don't feel bad about him "one upping" me there. And we both managed to grind basically standard-size ports that were capable of reaching 345 - 350 CFM at the peak lifts I was going to be cammed for... kind of like a decent (but not great) SB Chevy head.
8. I sent the ex-IMM heads w/ the Hughes CNC'd chambers up to Dwayne, along w/ a single out-of-the-box late-model Victor head I picked up off RacingJunk, and gave him the OK to see if he could duplicate a port in the ex-IMM heads like he did w/ the Procomp, and I could use that as a template for completing the rest. Well, it turns out, possibly since Brian received these heads from Edelbrock right after they switched from the original 75 cc chamber to the later 72 cc version, that both of these heads have significant core shift. And the core shift not only meant there was going to be a lot more grinding required, but that there was a good bit of variation from runner to runner in their as-cast shapes. Kwap...
9. I had to take a serious reality check:
a) I'm already strapped for time and still haven't got my engine completed w/ the parts that I have already on hand.
b) It was likely to take even longer to do a good job of porting the ex-IMM heads w/ the Hughes CNC'd chambers than I'd expected, and my own porting abilities might not result in the best possible job given the casting "stuff" Dwayne found after he started on 'em.
c) Some times I have more time than money, and other times it's the opposite. Although not ideal for either right now, I went ahead and asked Dwayne to go ahead and just do the whole bleepin' porting job. It's the only way I could ensure they'd get done in any timely manner.
(FWIW, that out-of-the-box late-model Victor I also sent for comparison, although not impressive at all in flow #s as it comes from Edelbrock, doesn't have the same serious core shift issues the other heads do. It was cast at a later date, so I'm keeping my eye open for another single late-model head that I could use to pair 'em up, and hoping that "E" got their casting issues worked after that first production run.)
ResultsThese aren't the "final" #s that will reflect an average of multiple ports' tests (i.e., the averaged #s could easily go down due to port-to-port variations impacting consistency). However, here's how things evolved w/ info that Dwayne has provided me to date:
1. Here's the #7 cylinder from the heads with the Hughes CNC chambers & IMM valve job, but before any porting:
Lift-------- I / E
.100---70.8 / 59.0
.200--142.7 / 119.0
.300--212.2 / 155.0
.400--266.5 / 172.8
.500--303.2 / 179.5
.550--311.8 / 179.8
.600--302.4 / 181.0
.650--304.2 / 184.7
.700--312.6 / 183.5
Dwayne's comments: "These new heads aren't even close to the early heads, which flowed 325+/220+ ootb. I don't remember them sounding like this either." (Ummm... that's not a compliment. It means they're noisy on the flow bench, and being noisy indicates an issue with the port design. - Brad)
Also, although I don't have the flow #s for the out-of-the-box late-model Victor head on hand at this writing to include, what I can say is they were definitely lower than the ones posted above. Unfortunately, these are simply no longer heads you should want to run "out of the box".
2. Same port w/ additional work, as described below:
Dwayne: "Did a bowl blend on the head with the chambers done. The bowl diameter where the "bulge" of extra crap was encroaching into the bowl was something stupid like 1.760. I opened it up to just under 2.00, measured even with the guide. That was a fair amount of hacking, but I didn't go after the guide boss or the area in the roof next to the boss. Pretty much concentrated on the bowls, and removed the ridges at the port entrance/exit. The exhaust bowl is still pretty small, although it looks like I took a bunch out compared to ootb."
Lift-------- I / E
.100--69.0 / 58.4
.200-139.0 / 116.5
.300-208.6 / 162.4
.400-267.2 / 197.1
.500-313.7 / 218.3
.550-326.9 / 223.2
.600-334.5 / 226.9
.650-340.2 / 229.9
.700-342.0 / 229.9
"Still sounds pretty ratty from around .550 up. The exhaust is still just too small (I think). I've started roughing in what should be the equivilant to how I did the PC head, so we'll see how that pans out. My overall impression of the direction Edelbrock went with these heads is........'it's just dumb'."
3. More work, plus intake back-cut testing:
Dwayne:
- "Port openings for both intake and exhaust are as ootb. So here's the thing... The head is pretty finicky about the back cut. . I flowed to .750 on all tests, and the flow dropped there on all tests except the OE port/OE chamber (well, the OE port/CNC chamber died after .550 then kinda came back but sounded awful)"
- "I had a feeling the back cut would pick the flow up pretty good until it backed up, then the question was how bad did it back up?"
Long story short, Dwayne tried a couple of different back-cut angles & widths to see how the back-cuts changed things. In his words, the heads "are quite responsive to this minor change."
V1 - First back-cut config tested
V2 - Second back-cut; per Dwayne, with a "shorter cut at a steeper angle"
Lift-----V1 / V2
.100--76.7 / 75.5
.200-157.3 / 152.9
.300-227.4 / 220.8
.400-283.5 / 279.7
.500-326.9 / 325.0
.550-339.0 / 336.4
.600-342.8 / 346.6
.650-346.6 / 349.6
.700-344.7 / 359.1
.750-342.8 / 343.9
4. Finished "template" ports
We talked over the results and decided to go w/ the "shorter cut at a steeper angle" intake back-cut because the nose-over point above .700” doesn’t seem to be impacted by changes in test pressure from 28” to 35”. Dwayne suspects the high-lift stalling issue is a result of the Hughes CNC chamber design (I see issues w/ it myself, and my older Hughes CNC heads show the same nose-over characteristic). FYI, my net lift will be under .700” even w/ 1.6 intake rockers on my cam.
The "template" intake & exhaust (no exhaust back-cut & no flow tube during test) #s are:
Lift-------- I / E
.100--75.5 / 53.5
.200-152.9 / 119.0
.300-220.8 / 157.4
.400-279.7 / 195.1
.500-325.0 / 221.9
.550-336.4 / 230.6
.600-346.6 / 236.8
.650-349.6 / 241.4
.700-359.1 / 246.4
.750-343.9 / xxx.x
Also, here are Dwayne's high-lift intake tests at 35” H20 while checking how this port & valve config handled more pressure (especially to see if it backed up worse under higher test pressure), considering it dropped off above .700”:
.600--387.6
.650--391.5
.700--399.0
.750--384.7
Comparing the original 28” H20 results to the 35" H20 converted back to 28” [ SQRT (28/35) = .8944 ] shows consistent results, regardless of the test pressure:
H2O – 28" / 28" conv from 35"
.600--346.6 / 346.7 < +.1 >
.650--349.6 / 350.2 < +.6 >
.700--359.1 / 356.9 < -2.2 >
.750--343.9 / 344.8 < +.9 >
Summary To Date--> Adjusting the runner volume for the built-in extension, I believe these heads can be considered a 250 - 255 cc head for comparison to traditional standard-location stock-size runner heads (e.g. Edelbrock Performer RPM, Trick Flow PowerPort 240). Dwayne even left the runner entry size the same as Edelbrock CNC'd it, so it's a true "standard port" entry. My older "standard port" Hughes CNC-ported Victors are opened up at the entry to 2.40" x 1.30", which IMO is sort of a "Standard Plus" compared to the original 2.30" x 1.25" entry size.
--> How do they compare to something like the Trick Flow PowerPort 240? Well, Dwayne's own TF test gives the advantage to the standard-location Trick Flow head in the .200 - .300" range, then the Victor's raised-runner "template" intake port above starts to pull away increasingly from there. Given the unknown variation of the "final" averaged tests, I'll say it's probably safe to estimate* the differences as shown below:
TF - PRH test of first-production-run Trick Flow PowerPort 240
EV - Estimated difference w/ PRH-ported Edelbrock Victor standard-port
Lift------ TF / EV*
.100-- 71.6 / +4
.200- 156.1 / -3
.300- 229.3 / -8
.400- 274.8 / +4
.500- 302.9 / +15
.550- 311.1 / +20
.600- 316.0 / +25
.650- 317.9 / +25
.700- 319.7 / +25
.750- 321.6 / +15
--> So what does this mean for Joe Average?
Probably... NOTHING!
Nobody is likely to develop a true standard-port CNC program like this for the Victor. Therefore, it's only available as a hand-ported option for someone willing to pay for it by the hour (or w/ the skills to port 'em themselves). Looks like I am that "someone"... at least using the "willing to pay" criteria.
And it's entirely possible that my own on-track testing in the future doesn't show any gains with these heads over the older Hughes CNC-ported Victors that I'm concerned are "too big" for my engine. If that's the case, I suppose it'll be Reality: 1; Brad's Hypothesis: 0.
But that's a lot of what Hot Rodding is about, right? Thinking about what "should" work better than what you have, then trying it out and seeing the results? Yeah, even for an old (er), fat(ter), ex-racer / Test-n-Tune junky like myself.
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