The dyno testing I've done with a stock type six pack compare to a single plane intake and 1050 CFM Dominator carb was that the six pack made 8 HP more at its peak RPM and similar torque.
All the stock type six pack set ups I know of make peak HP around 5500 RPM and peak torque around 4500 RPM, the bigger single carbs on a decent single plane intake make peak HP and torque a lot higher nearer 7000 RPM
I had a SS Weiand two piece 440 six pack intake I never tried or used

526” FAST build....... ported 906’s, 6bbl........ peak hp @6100....... with HP ex manifolds and 2.5” pipes.

Hot street 505, stage 1 rpms, solid cam, dyno headers, 6bbl...... peak hp @5800.

Mild street 446, 346’s with very minor blend, hyd cam, 1-7/8 headers....... peak hp @4900.


My total guesstimate for Greg’s build would be for it to peak in the 5600-5800 range with the 6bbl....... provided there are no lifter function surprises.

Dyno day is done. Thankfully the engine is healthy and no problems, other than a pesky rear main seal leak. I give up with that. I was so meticulous and so careful. Just doesnt make sense how it leaks. But, i will be pulling the pan and windage tray off this fresh engine to try again.
Anyway, the results are as follows:
Street dominator intake with open 1” spacer with 850 carb: corrected peak 610 hp @ 5300 (might be higher-didnt get this printout, and screen cutoff at this rpm) and 634 tq @ 4600.
Swap to iron six pack: best pull after jetting up twice: corrected peak 576 hp @ 5400 and 608 tq @ 4300.
Ended up at 64 jets center, 88 driver side/84 pass side outboards.
Then bolted on aircleaner with old used fram filter: lost 4 hp.
Difference from street dominator with spacer to six pack= 34 hp and 26tq

Very nice. Your numbers are highr than mine. Not that you should compare dyno numbers.

So, 4 jet sizes up on the driver side for both the front and rear carb? EGTs led you to that, I presume.

To what rpm did you make pulls? Did you see much drop off?

What exhaust?

Thanks for sharing.

I believe there is significant power being left on the table due to the non-ported iron six pack intake. I sent my aluminum intake to Hughes and let them do as much as they knew how to do on it. They spent a significant amount of time working on it to push their envelope of porting knowledge and ate half the hours they spent to learn just how far they could improve the flow. They got the port to port spread much closer than it is in stock form and gained a significant CFM increase per port overall.

Here's an article they published years ago on a bunch of intakes including the six pack. http://www.hughesengines.com/TechArticles/4portedintakemanifoldsupdated08272007.php

I'm tempted to buy a another new aluminum intake, bolt it to my motor to transfer my port alignment to it and send it off to Wilson to see what they can do to it with their best effort.

Comparison

Russ....... Greg’s test was done using headers.
You had the HP manifolds?

Yes, I did.

I'm not surprised with your numbers. If you had used a performance intake such as a Victor or Trick Flow the 610 number probably would have been a touch higher. A 30 hp drop when bolting on the six pack intake seems about right. Did you do a weight comparison? You probably added 30 lbs when you lost the 30 hp.

My pump gas 496 with TF240 heads and a hyd roller cam that is fairly close to yours makes roughly the same numbers using a port matched Trick Flow intake and a Holley Sniper EFI unit. I would guess that a good intake would put you in the 620 hp range if the carb is correct. The six pack intake can probably be improved although not too many folks like grinding on cast iron. If it is a hot rod then switching to the aluminum six pack intake and having someone like Hughes Engines do a deep port match would narrow the gap.

Russ, the jetting increased 7 jet sizes in both putboards and both sides. We left the 64s in the center. The last pulls with each manifold was to 6000 rpm. Peaks seemed to be well below that. And this was with their 1-7/8” dyno headers. Tubes come straight out wuite a few inches. I’m sure it would have killed a bunch of power if it was run with factory ex manifolds, like you ran.

I think when Greg gets the sheet from the run that had the 610@5300 rpm on it, the peak might end up being a little higher than that.
On the screen shot he has of that run, which as I understand it went up to about 6000rpm, only shows the data through 5300......... and to that point, the numbers were still going up.
The dyno printout should show the whole run, so the actual “peak” may not have actually occurred at 5300(but..... then again, it may have).

I don’t recall all the details of the conversation he and I had about the power expectations when we were discussing the cam choice....... but I think it basically did what was expected.

With the 6bbl, the numbers are within 7hp from 5200-5900.

Jbc426. Thanks for the references to porting the intake. Nut, like your cuda, this guy’s 71 Cuda is also a numbers matching 440-6 car. That’s the teason for this whole build. To take out the numbers matching block and tuck it away. So i didn’t want to touch his orig intake. And, he didn’t want to spring for a new alum edelbrock. He will never race this at the track. Just a street car he will hammer on ocassionally and do some burnouts with. I will definitely check out that article since i’m in the whole researching anything to do with six packs. Thx.
Btw, love that engine shot.

Andy, You are correct about the weight savings. That iron intake is redicilous. I believe it is 57 lbs, although i haven’t actually weighed it. So 30 lbs sound very resonable. But, the owner was not really looking for evey horsepower. That is more my goal and i influenced him to an extent. However, he was dead set on keeping his original iron intake and carbs on this new motor, so we lnew it would land wherever the power / torque landed. I think it did what it was expected to do. In a street car that prob had 325-350 hp at this point in life, it will be an awakening for him.

Yes Dwayne, i will get that sheet from the shop, but i don’t think it will be for a few weeks. I will send it your way and try to post it on here whenni get it.
And as far as our conversation, i think the cam choice was perfect for the intended usage. We knew it would never be raced at track. And his converter is not matched with a high horsepower build. So, you tried to keep it very streetable for power brakes and torque production from lower down. He thinks his converter is around 2500-2800. The sixpack was also a given from day 1. I am extremely pleased with the cam choice.

One thing for sure is,, That car will be a HANDFUL on the street !!!!! better warn him to be careful , especially if he has plain street tires.

Thanks. As shown in my previous post with the attached PDF, my jetting was less than your's on the 6 pack. I was running at about 13.0 on the A/F on that run. All of my best 4 bbl runs were recording A/F more like 12.3 to 12.5, so my 6 pack set up might have been a little lean in hind sight.

I pulled mine to 6000 too. I wish that I would have gone to 6300. My numbers were so flat from 5100 to 6000 that the "peak" power would change from 5300 to 5900 rpm on back to back runs with little or no change. I think its because of my cam. Just curious as to how your power tracked after peak.

Here’s a 10.9:1 505 with prepped/blended RPM heads, 6bbl, a 252/260-112 solid cam and my dyno headers(2-2 1/8 x 4).
The intake had some work done to it by a friend of the engines owner.
Timing was 35*, jets were 87/87 front and rear, 66 in the middle.
It doesn’t really have much of a power “peak” either.

On a cold water hero run it made just over 650tq/600hp.

I would take those numbers any day. Is that a Roller or flat cam? Prob a little too much cam for this application though, right?

That was a SFT cam........ def rowdier than what you just tested.

It’s important to keep in mind these motors weren’t tested on the same dyno.
And not only were they not the same dyno, but between your build, Russ’ build, and the one I tested...... they were tested on 3 different makes of dynos, using 3 different data acquisition systems.
Sure...... it’s possible they all agree with each other really closely........ but I wouldn’t trust them to be close enough to consider the results as truly “apples to apples”.

Exactly. From a comparison stand point, mine seems to be a bit high relative to your example and Greg's. But you know that I'm not about the dyno numbers, but the learning from changes. I do think the shape of power curves, change in power from motor changes, and jetting information is transferable.