[drewhelm1974]

Well, I finally had my heads flowed yesterday and have to say I am happy with the results! Using Jim Hand's book and Pete McCarthy's video I decided to give it a try. I probably wouldn't do it again, but it was an invaluable learning experience.

For the process I used a pair of carbide burrs (1 tree top with a rounded tip and 1 barrel), a couple different 80 grit stones, and a standard Abrasives deluxe kit.

Anyway, here are the flow numbers....

Port I/E .200 .300 .400 .500 .600
1 I 147.5 193.2 233.2 248.0 258.5
1 E 121.0 165.4 197.0 220.7 232.4
3 I 147.2 194.2 234.5 247.2 256.2
3 E 119.6 163.8 197.1 222.2 233.6

I was only going to have them flow 1 port then decided to have 2 flowed just to check for consistency. I took a LOT of time to make sure there was consistency during the process. I can't believe how well the exhausts flow!!! Considering both intake and exhaust numbers were still climbing at .600 I should have had them go to .650 atleast. With my cam and 1.65 HS Rollers lift will be at .610.

This is a set of 6X-4 heads that I had cut to take 1.77 exhaust valves and they did a competition 3 angle valve job after I was done.

Should make my 469 breath a bit better! what do ya think?

Drew

[blkcrow]

Congratulations-great numbers and think of all the money you saved!,I do my own porting,it sucks but its alot of satisfaction.

[eric65]

May have been ask before but cant find it
I would like to attempt same on my 6X-8
But where did you find the Jim Hand book and Pete video??
Thanks

[drewhelm1974]

Actually, a friend locally had both. Tommy Donovan. If you want to pay for shipping and the cost of the CDR I can burn ya a copy of the video. There are several sources you can get Jim's book from.

Drew

[Ron H]

PY sells the book, maybe the video as well. amazon etc. Great numbers!! I hope mine are around the same. Haven't had them flowed. One thing I noted is you are at 90% exhaust to intake flow ratio. What is your cam and the rest of your set up? Looks like another 11 sec pontiac is going to be tearing it up!!

[Z Code 400]

Very nice...my 6X-4's with the smaller 1.66" exhaust valves, peaked at .600" lift with 220.1cfm @ 28 in/H20 Intake and 195.0cfm @ 28 in/H20 Exhaust.

I didn't make any other changes since I felt the flow relation between intake and exhaust was optimal. I made very little (if any) changes to the short side radius and brought everything out to the confines of the gasket. I employed my usual 5-angle valve job and stock type (new) valves. The intakes had a 15° backcut on them as well.

Once I got the first two ports the way I wanted them (in terms of flow) I made a hard wax plug that allowed me to make all the other ports virtually identical. Very high polish intake and exhaust.

I am curious...how much of the pushrod bulge did you remove???...Robert

[Z Code 400]

Something interesting I found with respect to Edelbrock Heads for the Pontiac and flow numbers. According to their website, the E-Heads flow as follows:

Intake @ 28 in/H20

.100" 72 cfm
.200" 138 cfm
.300" 198 cfm
.400" 239 cfm

Exhaust @ 28 in/H20

.100" 56 cfm
.200" 106 cfm
.300" 141 cfm
.400 163 cfm

Comparing them to the low-lift flow values of my 6X-4 heads, I was surprised:

Intake 2.110" @ 28 in/H20

.100" 105.2 cfm
.200" 164.8 cfm
.300" 184.6 cfm
.400" 200.6 cfm

Exhaust 1.660" @ 28 in/H20

.100 85.3 cfm
.200" 124.9 cfm
.300" 130.1 cfm
.400" 158.7 cfm

The E-Heads don't really start to develop a lot of flow until your surpass .400" valve lift and most of the common Pontiac camshafts are low lift by design.

Interesting that your low lift flow numbers are even better than mine. Impressive!!!...Robert

[drewhelm1974]

Well, I am starting to wonder if my cam may not be optimal for the head flow numbers. I've seen and read the debates on single vs dual pattern cams. I already had the cam before I finished the port work. I had NO idea the exhaust flow numbers would be soooo good. The cam is an UD solid 255/260 @.050. Lift will be .594/.610 respectively with HS 1.65 rollers....depending on lash, of course.

Thanks for the info on the e-heads. I'm really glad to see the numbers are comparable.

I'll try to post a pic showing the intake bowl and how I shaped the pushrod bulge. I tried to make it look like the end of a football with a hole in the center....

This pic is before the valve job, intake valve was unshrouded and chamber polished.

[drewhelm1974]

Oh, I did as little as possible to the short turn radius. I tried not to change the shape or height at all, but just remove the sharp edges.

[70 bird]

Great numbers!! I am porting a set of 6x-4's now and I was wondering what size did you open the intake bowl to? did you go larger than 1.7? Thanks.

[drewhelm1974]

The intake is opened up to 1.79 which is 85% of the 2.11.

[Z Code 400]

Nice work...I did not go that far on my 6X-4's considering the low rpm nature of my 413. I was happy with near equal flow numbers intake and exhaust and improved low-lift flow numbers.

The flow curve had a definite peak at .455" lift which I why I chose .461"/.461" for my custom profile. I feel there is no sense lifting the valves much past peak flow on a street engine. Additionally, all valvetrain components 'see' the same load with equal lift figures, something we learned in endurance racing.

I added 6° exhaust duration (220°/226°) which should compliment the flow numbers with R.A.R.E. manifolds and crossflow muffler.

Your camshaft sounds like a good match...Robert

[Peckels]

Those are some good flow numbers .Im doing some porting on some 6x's right now and was wondering what your port width at the short turn is . Do you happend to know what the port volume is on your 6x.

[69*Goat]

I had my 6X-4's ported and polished and had the bigger 1.77 exhaust valves put in.
My flow numbers came in at this:


Inches Int. Exh.
.200 135 117.
.300 194 155.
.400 235 177.
.500 250 190.
.550 255 195.

I have been told that these are some pretty good flow numbers.

[Larry Navarro]

Originally Posted by 69*Goat

I have been told that these are some pretty good flow numbers.

Yeah, and the car pulls like a frieght train with the Summit #2802 cam too!!

[drewhelm1974]

Honestly, I have no idea what the port volume is....didn't have them CC'd.

I'll have to get my buddies snap guages back and check the width at the short turn. I believe it is really close to 1.75. I know the port is a little wider at the short turn that at the port roof.

[69*Goat]

Originally Posted by Larry Navarro

Yeah, and the car pulls like a frieght train with the Summit #2802 cam too!!

Shhhhh!!!!!!!! It's a secret!!

[Skip Fix]

You can borrow my burrette if you want Drew.Or I can give you a couple of 60cc syringes.

[Peckels]

My short turn width is at 1.50 right now . I believe stock is around 1.45. My heads are currently at 165 cc's . I got the heads matched to the RA IV gasket. And have the bowls out to 85% . And the pushrod bulges out to 1.030 Its obvoius that the wider you make the port at the short turn the more air it will flow but I only want 265 cfm and would rather be on the safe side of wall thickness with these heads. I guess I should just go get a flow test right now to see how close I am to 265.

[GTOLIB]

good numbers,, i followed Pete M articals when I did mine , I was fun and yes learned alot, I practiced on a extra head first, then did the heads,I found the hardest part was getting all 8 flowing the same.