Atilla the Fun

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Atilla the Fun

Good porting is not about removing as much material as you can, it's about removing as little as possible.
Especially on already-good heads like these. Richard Maskin gave them a good basic design, I'm just cleaning up the casting and machining issues to get the ports back to what Maskin intended.
Bear this in mind when looking at the pics.

Atilla the Fun

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Atilla the Fun

still having difficulty getting good pics of the exhaust short turns, even with the dental mirror.

Atilla the Fun

Not done yet, but the bulk of the material removal is done. More pics tomorrow.

one92rs

iTrader: (5)

cool deal. i always wanted to see pics of this type deal. now i cant wait till you do that set of vortec heads. that will give me the guide i need to do mine.

Atilla the Fun

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one92rs

iTrader: (5)

money seems to be getting a little tight. so i am going to try it myself.

Atilla the Fun

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Atilla the Fun

Porting secrets:
electric beats pneumatic, so long as you can control the speed.
Port or polish for an hour, then walk away for a half hour
don't forget safety glasses, earplugs and a breather mask of some sort.
flourescent or LED light is best, smaller is better
also have a dental mirror and a red magic marker
always believe your fingertips over your eyes
if it feels wrong, it is wrong, except around the intake seats.
use the red marker to indicate what feels wrong, this helps you grind in the correct place.
have spare valves to protect the seats when grinding in the chambers
smaller carbide diameters are better, but can do more damage quicker if you slip
Always operate in a sweeping motion, never just hold the tool still anywhere, no matter what. You can vary the pressure you're applying.
if porting aluminum, frequently use a silicone based liquid lubricant
if porting aluminum, keep a small sharp pick handy for cleaning clogs from your burr
stones and flap wheels and buffs are dumb, all you need is oval carbides and tootsie rolls.
never do any polishing in any intake port unless it's a direct injection engine design
Never keep going if you need to stop and pee.
turn your cellphone off, set an away message if you want, but turn it off. If you can't, then don't do porting until you can. No exceptions.
Work indoors.
A wheeled stool is best.
Plan on making a huge mess. You'll make lots of dust, it gets everywhere.
A wood work surface is best. Plan on it getting damaged.
Have at least 6 blocks of 2" x 4" by 6" wood for use positioning the heads.
I'll add more if I think of any.

Primetime91

iTrader: (15)

To anyone who is really following this, sorry to say but I will not be having the darts flow benched.

I would post before/after ET's and MPH to give a decent idea of the gains netted from the porting, but I'm having the heads milled down .030", and changing intakes from a Victor Jr to a Performer RPM Airgap at the same time, so any changes couldn't be attributed directly to the porting. Should register "faster" on the butt-o-meter though

You guys are gonna have to wait on the Vortec's though, if you want real numbers to look at

Atilla the Fun

I do have before and after numbers on the Iron Eagle 180s I did back in late '04, if anyone wants them.

one92rs

iTrader: (5)

man i have some vortecs yall are welcome to play with and i will get them flowed no matter what i have to do.

Atilla the Fun

I have results from a half dozen sets of 906s and 062s I did in late '04, from stock, through my current stage 1 and 2, to 2.02/1.60 stage 3s. 2.02" intake valves are necessary to get past about 245 cfm, but the porting necessary to get over 270 cfm is not for DIY porting by first-timers. In fact, stage 1 doesn't even touch the intake ports except for gasket matching. The intake ports are just too sensitive. The exhaust ports, not so much. In fact, doing the exhaust guide bosses by themselves does nothing for the flow bench numbers.
I have my own pair of virgin but used '96 #906 K1500 truck heads on my shelf, waiting on me to find a good use for them. I have the matching aluminum GMPP EGR carbureted intake manifold sitting on top of them.

z28freak84

Im interested in any and all of your results....! Especially the Vortec stuff... Please Share.

Atilla the Fun

before giving numbers, the most important thing to know is that these were my results, and you probably won't do quite as well , but numbers are good for seeing how much improvement is available in whichever heads you are considering.
I have probably 30 pages of Vortec results from late in 2004, because I had access to a Serdi, and unlimited access to a new SuperFlow 1020 bench with Every feature imaginable.
My numbers are low because I was testing at an elevation of 4200-4300 feet above sea level. SuperFlow did send a guy out to calibrate it, but even so, my numbers are a bit low compared to most of what you read, but they were consistent.
I never did use a length of header tubing on the exhaust ports, but I wanted to, for the sake of better numbers. Since I couldn't, my exhaust numbers are way lower than anyone else's. But since I was doing before and after testing of my own porting, it hardly matters.
The numbers I'm giving are averages of 8 ports, not 1 best port. Some results you find from other sources will have the low-lift numbers from a port that did well at low lifts, but the high lift numbers from a different port. I don't believe this is honest.
I did all my SBC testing on a 4.060" bore fixture. Except the ones I did on a 3.766" bore fixture, but I'm not giving those here.

Atilla the Fun

Dart Iron Eagle 180 cc with 2.02 / 1.60 valves: stock intake ports: .100"=55, .200"=113, .300"=175, .400"=207, .500"=228, .600"=223. After mild bowl blending: .100"=61, .200"=124, .300"=181, .400"=223, .500"=243, .600"=242.
stock exhaust: .100"=46, .200"=95, .300"=129, .400"=153, .500"=166, .600"=172. After heavy porting and polishing: .100"=53, .200"=110, .300"=144, .400"=171, .500"=186, .600"=195
I wanted to swap these stainless swirl polished valves for some better ones with the same features but also with undercut stems and 30-degree back cuts, but the customer refused. I also felt these needed to be gasket matched to the next larger Fel-Pro intake gasket, but again the customer refused. I believe that alone is why flow peaked at 243. That first, then valves, would have gotten closer to 260.
Compare these to my test of unported Pro Topline iron 180cc with fancy 2.02 / 1.60 valves, right out of the box: .100"=66/54, .200"=129/105, .300"=180/137, .400"=219/160, .500"=245/175, .600"=255/180. Not quite AFR, but maybe if I had done some porting to them.
But my employer didn't check AFR numbers, he just compared them to the DIE180s I'd just done, declared I couldn't improve the Pro Toplines, and bolted them on his truck the same day. A$$. I improved every other head I ever touched with a carbide burr. Shoulda at least let me polish the exhaust ports and re-flow them.

Atilla the Fun

882s, no before numbers, good aftermarket undercut-stem stainless swirl-polished valves with 30 degree back cuts, 1.94 / 1.60", 5 angle valve job, intake ports mildly cleaned up, exhaust ports fully ported and polished:
.100"=63/40, .200"=126/91, .300"=178/136, .400"=206/153, .500"=214/169
These were customer heads done to customer spec. I wasn't happy with the results and begged to do more. customer didn't pay for the flow bench testing, so never saw these numbers. That's why there are no before numbers.

Atilla the Fun

stock vortecs: .100"=63/46, .200"=121/98, .300"=177/132, .400"=217/140, .475"=238/142, .500"= ???/143
just swapping intake valve for swirl polished stainless with undercut stem and 30 degree back cut: .100"=65, .200"=133, .300"=188, .400"=223, .475"=238, .500"=225. That's the stage 1 intake port. Stage 1 exhaust, with the fancy valves, plus fully ported and polished, but still with 1.50", came out like this: .100"=50, .200"=109, .300"=140, .400"=159, .500"=167.
So I put them on the Serdi, to go up to 1.60" exhaust valves, with 30/45/60 degree cuts, then a de-shrouding cut that ended with a 15 degree angle at the bottom, then a 75 degree bowl hog. That makes 5 angles. A bit more porting to blend the 75 into the port, then polish over that last porting, bumped the results nicely. Again using the fancy valves. .100"=57, .200"=114, .300"=149, .400"=167, .500"=177, .600"=181
Those are still entry level results that anyone should be able to get very close to if they just follow the instructions I sent to one92rs. PM me if you want a copy, they go into more detail than what I expect to show next week, but they don't have pics.
With big valves, and more extensive intake port grinding, my best 906 results from '04 went like this: .100"=67, .200"=138, .300"=201, .400"=249, .500"=268, .600"=269. Those are my big-money secret, so don't ask. There are a few things in life that you just don't give away for free until you're literally on your death bed, and that's one of them. Sorry. But, for a consolation prize, go to the RHS website, and you'll find they are advertising their 2.02"-valved vortecs are doing better than this, but on a 4.200" bore, which cheats the numbers up.

Atilla the Fun

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Guest

I can drive over there and get your pics to upload for you if they do unfairly ban you. Just e-mail me the comments on the pics, I'll post them too. You've helped me enough times, driving over here and wrenching on my cars.

Atilla the Fun

Vortecs are here, so pics this afternoon.

skinny z

This I want to see.
(Any experience with Edelbrock 60739's?)

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