The shop that's porting my heads (Champion Racing Heads) contacted me today. The port work is done on the heads. The chambers were at 120cc when they arrived. They measured max flow of 330cfm on the intake side which is very close to what I recorded on my friend's flowbench before sending the heads out. Both benches are SF600. Champion felt like the intake runners were TOO big making the port lazy. They epoxied the floor of the runner and raised it ~.280". They then ported the chamber, worked the short turn radius and raised the roof area (among other things). I also sent them my manifold so that they could make sure the alignment was correct. They ended up epoxying the intake runner of the manifold too in order to get the port alignment correct. He gave me the flow numbers for the #6 port. Below are the original flow numbers that I recorded on my friends SF600 as well as the numbers Champion provided me today:

Intake
======
lift original New
.200 158.3 186.5
.300 222.9 260.7
.400 272.7 312.7
.500 299.0 347.6
.600 312.2 357.2
.700 316.6 366

Exhaust
=======
lift original New
.200 134.3 143
.300 179.2 199.2
.400 194.9 246
.500 235.8 275.6
.600 251.6 292.5
.700 264.1 299

Just looking at the raw numbers this shows about a 14% increase on average. After the port work the chamber ended up at 122cc. I'm having the heads cut down to 119cc. I ordered new pistons yesterday. The new pistons are Wiseco with a 48.4cc dome. This should put the compression just a tick under 13:1. I also ordered a new cam .726 254/260@.050 108lsa. Installing new Crower I-Beam rods and a crank scraper. The rotating/reciprocating weight will be down a good bit as well. Planning to spin the new engine to 7k. This thing should be making HUGE torque for a 460ci engine. The port cross sectional area is a good bit smaller than before and the flow is significantly improved. I should have the heads back early next week. The block is being machined right now. I hope to be able to start assembly in the next two weeks. Once assembled it will be put on the dyno. I'm shooting for 750hp/650tq. I'm not sure if I'll get there but that's the goal smile.gif I'll post some pictures of the heads after I get them back.

Wow thats a killer port job. The midrange flow numbers are exceptional. Correct me if I'm wrong, but didnt you have the heads originally flowed with a test pressure of 25"? Do you know what bore fixture the heads were flowed with, before and after? And do you know what the port volume is now?

Originally posted by -SS454-:
Wow thats a killer port job. The midrange flow numbers are exceptional. Correct me if I'm wrong, but didnt you have the heads originally flowed with a test pressure of 25"? Do you know what bore fixture the heads were flowed with, before and after? And do you know what the port volume is now? Yes, I'm pretty pleased mathematically speaking ;) As always, the proof is in the pudding. Both sets of measurements were taken at 28". The flow numbers that I recorded on my friends flow bench were done with a 4.125" bore fixture. I believe Champion used a 4.310" fixture. I'll ask to be sure. Not sure about the port volume, but I'll ask graemlins/thumbsup.gif

maybe i am totally wrong, but i thought i read somewhere that epoxy can fail, and isn't a good idea, but it seems plenty of people use it? The numbers are outstanding!

Besides a window net, what else do you need to run under 10.0? smile.gif

Ok. I got a clarification from Champion. They used a 4.400 bore fixture to flow the heads. I asked about port volume, they said that isn't important to them. They said they're more concerned about crossectional area. The port is ~2.9 square inches at the pushrod.

Cody, I had heard the same thing about epoxy. I think that is from the old days when nobody really knew how to use it and/or the composition of the chemicals wasn't as good. Champion builds heads for a lot of off shore boat stuff. He has expoxied heads that have been in service for nearly 10 years in those applications and there isn't an issue. The surface has to be knurled or roughed up a little for the epoxy to bond correctly. He assured me it wouldn't be an issue. Good question, though.

Mike, I think a chassis certification is also required. However, even if the engine will be making enough power to push the car into the 9's there is no way that my suspension/tire combination would be able to stand it. Maybe a mini-tub on the horizon smile.gif I'll wait and see what it runs first. Hell, it may slow down tongue.gif

graemlins/thumbsup.gif I like it! Giving up on wimp, errr, pump gas? :cool:

Sounds good Ken,

Really looking forward to seeing how well it performs next season.

Wow!! That's what you can get using a professional shop. Impressive!! graemlins/thumbsup.gif You'll see low 10's for sure!!! Mine did 10.3 spinning like crazy off the line so with your dialed suspension it's going to be great. Take another look @ that cam. With the flow #'s you now have you might be able to use alittle more duration. With the new found power and 10" tires you can sacrifice some torque down low for some on top. just a thought.Keep us posted.

Mike,

No more pump gas. This a bracket race only car effective immediately smile.gif (like I was driving it on the street much this past year anyway).

Thanks, Todd. I'm pretty excited as well.

TWC,

I too am anxious to see wht it will run. I had the chassis working pretty good the last time out, but I was also on a damn good track. My home track isn't always prepared so well. I'm sure I'll have more work to do on the suspension. As for running more duration... You're right, and several others have pointed that out as well. However, my design for this rebuild from the start was to have an upper limit of 7,000RPMs. I feel the engine can go longer between refresh as opposed to running say 7,400 every pass. Depending on the outcome of the dyno testing I may be shifting at 6,800. A little smaller duration at .050 as well as the relatively small LSA will make for some honking torque and that's what it takes to get nearly 3,800lbs down the track.

So all is about $$$. How much ;)

The port work is costing $850 U.S. That does not include shipping charges.

If you mapped the ports which you paid for, you would own the programme, no? Then, you take the head to Canfield and say hi, my name is Ken and have I got a deal for you.....

How much difference does the bore fixture make using two different sizes for comparison? How do the intake port sizes compare to an iron oval port? Are they still quite a bit larger? My 781's were gasket matched and polished up pretty good and he also opened up and reshaped the exhaust ports too. I had the option to have them flowed,but I didnt feel it was necessary as I'm going to keep the shift point below 6500.

Originally posted by ejrempel:
If you mapped the ports which you paid for, you would own the programme, no? Then, you take the head to Canfield and say hi, my name is Ken and have I got a deal for you..... I wish smile.gif Canfield has a CNC program they run on their newer heads. The CNC program is no doubt the product of many hours spent working on those heads.

Originally posted by Rapid Robert:
How much difference does the bore fixture make using two different sizes for comparison? How do the intake port sizes compare to an iron oval port? Are they still quite a bit larger? My 781's were gasket matched and polished up pretty good and he also opened up and reshaped the exhaust ports too. I had the option to have them flowed,but I didnt feel it was necessary as I'm going to keep the shift point below 6500. Bob, there seems to be some conflicting opinions on the subject of bore fixture size. Champion recorded a max flow of 330CFM on my heads when they received them, although I didn't ask on which port. I measured 329cfm on my friends flow bench so that's pretty close even though we were using two different fixture sizes. I think it depends on the size bore in question, head chamber size and shape, how the head is positioned on the bench, how you're measuring valve lift, how a particular port is shaped/flows, etc... IOW, there are too many variables to say with any certainty how the two different fixtures would affect flow. As for how my heads compare in port cross-section area to an oval/iron head, I'm not sure. I've never measured the later. I now have a good set of mics (inside and outside). If you like I'll measure my heads when they come back to give you something to compare to yours. The reason I had the heads flowed before and after is to try and measure a change. I will be flowing these heads again myself after I get them back as each flow bench (along with the variables listed above) can produce different readings. It will be interesting to see what sort of power the new engine will make.

Superflow has a formula to calculate theoretical HP. The formula is CFM x .265 x # of cylinders. With mine that works out to 366 x 265 x8 = 775.92. That's pretty close to the 750hp I'm hoping for. This of course assumes that the engine is capable of pushing that much air ;)

The bore fixture no doubt makes a big difference on flow numbers. A 4.50" fixture can be worth 25-30 cfm (depending on head), over a 4.25" fixture.

Originally posted by -SS454-:
The bore fixture no doubt makes a big difference on flow numbers. A 4.50" fixture can be worth 25-30 cfm (depending on head), over a 4.25" fixture. May I ask what you're basing that information on? What lift, runner, head? Have you done back to back testing on a flow bench? From what I've seen I'm not 100% sure that's a universal truth (read the variables I mentioned earlier). I know that all the major manufacturers are testing witha larger bore fixture (usually 4.60) and I'm sure there is a reason for it. Just curious what you might know about the effects of different size bore fixtures on different applications. As per my comment above it didn't seem to make much difference in my case.

Thanks Ken...I would be interested in the measurements.

[qoute]The bore fixture no doubt makes a big difference on flow numbers. A 4.50" fixture can be worth 25-30 cfm (depending on head), over a 4.25" fixture.[/quote]

Yep, it sure can, I'll bet if their measured
on a 4.125 those numbers will drop.

Question, how much ( if you don't mind me
asking ) did those Canfield heads cost you.

One thing to remember thro, it's the port
shape and cross section that really matters,
not saying flow isn't important, cuz it is.
I'd be interested in knowing what the port
volume is.

Originally posted by One-Bad-70:
[qoute]The bore fixture no doubt makes a big difference on flow numbers. A 4.50" fixture can be worth 25-30 cfm (depending on head), over a 4.25" fixture.Yep, it sure can, I'll bet if their measured
on a 4.125 those numbers will drop.

Question, how much ( if you don't mind me
asking ) did those Canfield heads cost you.

One thing to remember thro, it's the port
shape and cross section that really matters,
not saying flow isn't important, cuz it is.
I'd be interested in knowing what the port
volume is. [/QUOTE]

Thanks for choosing my post for your first ever reply after just registering on the site :rolleyes: Can you say troll?

It's a very interesting post, I'm thinking
of going with a set of Cantfield, a friend
just made 730HP on pump gas with a 540 CID
and went 10 flat off the trialer, I'm impressed.
It's a 70 Chevelle all steel except the hood.

He did his own heads, claims all he did was
clean them up, but he's also got big cubes.

Oops. looks like I offended some one.

Ken, my thought on the bore fixture size vs the flow number differences seen.

I'm thinking that maybe your head porters flow bench is a bit more conservative than your buddies was. This might account for very similar before flow numbers, yet the head porters bench was using a larger bore fixture diameter.

Just like dynos, no two flow benches will flow exactly alike, as you already mentioned.

Seems logical to me, so lets just let it go at that :D .

I'm fully convinced that a larger bore fixture will increase flow numbers my a measurable amount mainly due to valve unshrouding. Why the manufactures of heads advertise the larger bore diameter bore fixture flow numbers? Two reasons IMO...one is Marketing plain and simple...higher flow numbers sell heads. The second reason to a lesser extent may be that larger bore 500+ ci engines are more common place now than in the past.

Kjett, I have info of a back to back comparo of AFR 315 heads done on a 4.25 and 4.50 bore fixture. It was 282@.400, 348@.600 with the 4.25" and 315@.400, 375@.600 with the 4.5".

The 4.125" bore fixture your friend used was basically a big bore small block fixture, since no BBC has a 4.125" bore. Thats why your original head flows seemed "low". You mentioned that the heads measured 330 cfm, but your figures show 316 cfm max, so I assume Champion baselined it on the 4.40" fixture and got 330 @ .700. If thats so, then you got nearly an 11% increase at .700, and probably even more at lower lift. Impressive for staying with what sounds like a relatively small port volume.

10secBu is 100% right. Big bore big blocks are very common now, so a 4.50-4.60 bore fixture is usually used. And the big flow numbers make a good selling pitch.

Here you go Mikey right from AFR site

All flow figures taken in this test were recorded using a 4.250 bore fixture. Current chamber designs and valve sizes used today (typically 2.250 - 2.350 for BBC intake valves) would show better results being tested on the larger 4.500 bore fixture. (Primarily due to unshrouding the valve with the larger bore size.) With so many production GM blocks, as well as the aftermarket, starting at 4.500 inches in bore size, we feel this is much more representative of the current trend in Big Block Chevy engine building. All published flow figures from AFR were obtained using a 4.500 bore fixture. However, the fact that all the information obtained at Westech was recorded using the same bore size (4.250), the same flowbench, the same operator, etc., this still proves to be a valid test and comparison, eliminating many variables that could potentially exist evaluating and comparing flow data.



The following information was recorded the same day at Westech, flowing the exact same AFR 315cc intake port, simply swapping test fixtures to the larger 4.500. These flow figures are almost identical to the published figures from AFR. They are

Originally posted by -SS454-:
Kjett, I have info of a back to back comparo of AFR 315 heads done on a 4.25 and 4.50 bore fixture. It was 282@.400, 348@.600 with the 4.25" and 315@.400, 375@.600 with the 4.5".

The 4.125" bore fixture your friend used was basically a big bore small block fixture, since no BBC has a 4.125" bore. Thats why your original head flows seemed "low". You mentioned that the heads measured 330 cfm, but your figures show 316 cfm max, so I assume Champion baselined it on the 4.40" fixture and got 330 @ .700. If thats so, then you got nearly an 11% increase at .700, and probably even more at lower lift. Impressive for staying with what sounds like a relatively small port volume.

10secBu is 100% right. Big bore big blocks are very common now, so a 4.50-4.60 bore fixture is usually used. And the big flow numbers make a good selling pitch. I'm not doubting that the bore fixture makes a difference, just when and how much of a difference. Here's a link to the flow numbers (posted a originally a couple weeks ago) that I myself recorded for my heads before they were sent to Champion using an SF600 flow bench at my friends shop:

http://bellsouthpwp.net/k/_/k_jett/Images/Canfield/flownum.mht

As you can see max flow was 329.85 on several cylinders, not sure which figures you're referring to. Champion measured max flow at .800 lift same as we did. The only reason I only provided the new numbers through .700 lift is because that's all I asked them to focus on. My new cam has a gross lift of .726, which nets out to about .685 with .25 lash and valve train deflection. So back to my original point, I don't see where in this case the bore fixture size made that much of a difference. I'm certainly no flow bench expert, but I did spend about 10 hours using one a couple weeks ago. Wouldn't you think that if you move the head such that the intake valve is closer towards the center of the bore fixture that you have unshrouded the valve? How much do you think this would affect the readings? I already have a pretty good idea as I tried it myself ;) Try experimenting for yourself the next time you have access to a flow bench. You might be surprised what you find.

I'm sure every head responds differently, but I didn't see evidence that supports this theory with my heads. BTW, agree 100% on the marketing numbers graemlins/sad.gif

Oh, I'm gonna weigh in. When I was flowing a lot of heads a couple of winters ago, I would be sure to place the head on the fixture in the same way every time, to eliminate variables, because shrouding is a big deal. We have only to think about good port/bad port in a BBC, and the huge flow differences we see there because the incoming charge on every other cylinder slams into the cylinder wall to a greater degree. As to the improvement with epoxying: you know, it makes sense because the pro stock boys seem to be downsizing and making more power, no? It's all about efficiency.

kjett, here's how it goes, piston speed determends cross section size, you need X
amount cross section for a particular rpm range
and from what you explained", your head porter saying, the ports where to lazy. So he had to fill it in with epoxy, what he's talking about is velocity, if the ports to big there won't be
enough velocity to fill the cylinder bore. at
rpm range your looking for,that's very important. That a lone will increase flow numbers. Sounds like
to me he really knows what he's doing, and you
got your moneys worth. As I said before port shape
and cross section are most important.

Sure flowing with a bigger bore fixture will
produce more flow, my guess about 8 to 10 cfm
more, not really a big deal, when you consider
whether or not it will fill the cylinder.

The figures i was refering to were the ones you posted, that didnt go up to .800" lift, so I couldnt see the 330 cfm. I looked at the flow numbers, and I'm almost certain those advertised numbers by Canfield were on a 4.5" fixture, if not a 4.60". Compare those to the new mid range flow numbers, and its easy to see the gains. Ultimately they are just numbers, and the true test is when u get it to the track. Wolfplace would be a good person to talk to about flowbenching, as he has quite a bit of experience flowing heads with different fixtures.

Hi Kjett, This flow thing is quite an interesting subject. Increasing the flow while decreasing the size of the port should provide a few tenths improvement. My son had a 13-1 (482) in his Chevelle and put a set of 335 CNC Darts in place of the previous square port Chevy iron heads. This reduced the weight by 65 pounds or so and the car picked up about 3 1/2 tenths. I think you will see low 10s @ about 130-132 MPH with your changes. There is a comparison flow chart on the Chevy Hi Performance site. The AFRs picked up bigtime in the midrange flow numbers using a 4.5 bore fixture vs. the 4.25 one according to Westech. On the only head i've had checked on a Superflow 600 the exhaust didn't come up to expectations and the intake was a little low in the mid lift numbers. We are going to try this head anyway on a new 598" motor and see what happens. I'll post it's results no matter what, good or bad. Darin Morgan said flow doesn't mean much anyways; go figure. You might read the new article at the back of the National Dragster ( Dec.10, 2004 issue 46) page 154 written by David Reher. Some insite as to why the Pro Stock Cars continue to go faster with mostly the same parts.

OK. Thanks for all the responses everyone. Like has been said, at the end of the day these are just numbers. The real test will be at the track and that won't happen for another couple months. I'll still post some pics of the heads when I get them back. I'm interested to see how the port was reshaped.

Let me guess,,,raised floor,raised roof,and more radiused port,large oval or roval...My axles,c clip eliminators and rear end support cover are here today,and motor is supposed to be done today. The first track around here opens the first weekend in Feb. weather permitting and I plan on being there graemlins/thumbsup.gif

Your weather is kinda like ours here at Tulsa Robert so i think early Feb. is wishful thinking. Ours is supposed to open back up in late March with the first shootout in April.

Harold...MoKan usually gets one TNT in Feb. then its March before the weather moderates. I think I've made TNT at Mokan the first weekend of Feb. the last two years and the weather was near 70,then old man winter reared his ugly head again :(

Interesting observation Robert. I imagined the ports would be more rectanguar, however; with the width of the port reduced. I've always imagined air's momenteum forcing itself alongside the side of the port and not on the floor as the piston delta pressure sucking air through the carb I felt the bias of the carb to the intake valve. Am I making sense? Looking at a of older set of rec port heads it gives the impression that the floor of the port is shaped as an airplane wing to suck air from the start of the tract to the low pressure short turn radius. I got the idea from the newer LS1 heads that have over a 200cc intake track and look like recangular slots than ovals. Since I've seen the LS1 heads I've always looked at a intake port sideways.

Several of you had inquired about the port volume and runner shape after the port job. The port volume in the big runner is 300cc. The port shape is still rectangle smile.gif

======
lift original New
.200 158.3 186.5
.300 222.9 260.7
.400 272.7 312.7
.500 299.0 347.6
.600 312.2 357.2
.700 316.6 366

Exhaust
=======
lift original New
.200 134.3 143
.300 179.2 199.2
.400 194.9 246
.500 235.8 275.6
.600 251.6 292.5
.700 264.1 299


MY flows for same heads.

Orginal
0.050 48 24
0.100 126 50
0.200 159 96
0.300 245 134
0.400 274 167
0.500 302 227
0.600 342 233
0.700 359 245
0.800 380 265


Ported
0.050 50 24
0.100 80 48
0.200 159 108
0.300 250 157
0.400 297 186
0.500 338 223
0.600 362 239
0.700 383 254
0.800 400 291

28IN/HG With 4.500 bore 2.25/1.88 valves. Chamber/port job, no expoxi

What did they do on the exhaust? Mine were not any good at all ,(

What did they do on the exhaust? Mine were not any good at all ,(My only guess is maybe Ken's were flowed with a pipe on the exhaust?

His seem to be measurably better than yours up to .500" lift on the intake side.

Mine is flowed without pipe. Made alot with a pipe and even more with a pipe in a Non header Direction ;)

May I ask what you're basing that information on? What lift, runner, head? Have you done back to back testing on a flow bench? From what I've seen I'm not 100% sure that's a universal truth (read the variables I mentioned earlier). I know that all the major manufacturers are testing witha larger bore fixture (usually 4.60) and I'm sure there is a reason for it. Just curious what you might know about the effects of different size bore fixtures on different applications. As per my comment above it didn't seem to make much difference in my case. It seems that trying to equate flow to horsepower is very difficult, Ken. I was told by a S/S engine guy from this area that lots of variables can affect your flowbench data. For instance one of our shootout racers had gotten a maximum flow on his Brodix -2 Xtras of 428 CFM on one bench and on this guys bench only flowed 365 CFM. He builds primarily Super Stock Hemis, some of which are pretty fast. He claimes the Hemis typically flow 440 CFM and the last one made 906 H.P. but didn't say at what RPM. The big 565 C.I. rat motor made 902 H.P. on his Superflow 901 Engine Dyno. Any leak around the head will show large flow increases and this guy claimed it is necessary to seal the head to the flow bench with a head gasket to eliminate leaks. My son's AFR's showed 373 CFM on a JKM bench and 426 on a Superflow 600 bench with a larger bore size (4.31 vs. 4.50). The motor flys so it seems to flow very well. I'm pretty sure it is making big power as it is about 8-9 MPH faster than the 540 it replaced with similar gearing.

Harold...MoKan usually gets one TNT in Feb. then its March before the weather moderates. I think I've made TNT at Mokan the first weekend of Feb. the last two years and the weather was near 70,then old man winter reared his ugly head again :( There are going to be four TNT days in February here Robert, weather permitting. Looks like this weekend is a go with now only a few sprinkles forcast for early Saturday. My friend "Al" is going to run his S/S Camaro with the new 439" S/S "C" engine he just built. It made 770 H.P. at 7200 but held within 15-20 H.P. of the max to about 8000 RPM. The Dyno is a little happy so no telling how fast it will be. It ran 9.96 @ 132 with the old "D" automatic motor but it had lots of problems with the heads.

What did they do on the exhaust? Mine were not any good at all ,(
Godsend,

I'm not sure what you're asking here. This was a full tilt port/epoxy job. No epoxy on the exhaust side although the runner was really opened up. The heads were flowed with an exhaust radius and a 4.31 fixture at 28". The focus of this work was on raising the mid lift flow numbers of the heads. This engine went 9.95@135 earlier today on a shake down pass in my friend's 67' Camaro. Should run 9.80's before it's all said and done :)

Thats really fast for a 460" motor Ken. It would appear that they did a good job on the heads. The only info. thats missing is the run weight of the Camaro, and maybe, weather conditions. Good job on first time outing.

Thats really fast for a 460" motor Ken. It would appear that they did a good job on the heads. The only info. thats missing is the run weight of the Camaro, and maybe, weather conditions. Good job on first time outing.
Thanks, Harold. I was really happy to see it running so well. I just spoke to Gordon on the phone. He scaled the car at the track today and it weighed 3,355lbs w/driver and fuel. Neither of us had our weather stations at the track today. He made that pass at slightly after 4:00PM. I would guess the DA was ~2,000'-2,500'. Definitely has quite a bit more in it with some fine tuning, seat time and a little better air. First he needs to get his cage finished (currently a 6pt roll bar).

Godsend,

I'm not sure what you're asking here. This was a full tilt port/epoxy job. No epoxy on the exhaust side although the runner was really opened up. The heads were flowed with an exhaust radius and a 4.31 fixture at 28". The focus of this work was on raising the mid lift flow numbers of the heads. This engine went 9.95@135 earlier today on a shake down pass in my friend's 67' Camaro. Should run 9.80's before it's all said and done :)

Then ill have to open up My Exhasut runners a bit more then ;)