I want to be accurate in my sig

Before I got my heads, I asked World what I should do, saying I intended to follow Standard Abrasives' guidelines and telling them what else I had planned. They endorsed SA's instructions, but said work on the bowls (they didn't tell me not to do the rest).

Well, after seeing them as-delievered, I understand why they recommend working on the bowls. But, I'm going the full SA route as well: matching intake ports to the gaskets, cleaning up the intake port cast surfaces, opening up the throats to 85% of valve diameter (as recommended by SA), smoothing the short-side radii, smoothing out the valve guide intrusion into the ports, polishing the exhaust ports and chambers.

My point: When I think "porting", I think not only of opening up and smoothing the ports for more flow, but re-contouring them to change the flow characteristics, matching flow from cylinder to cylinder, things like that.

I've heard bowl clean-up referred to as "pocket porting" - if that's all one did, could they be called "ported" heads? If not, does my other work qualify as "porting" the heads?

Technically speaking...

------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. 2-1/2" cat-back, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 CC system w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker 2055 headers, 3" Catco cat & 3" catback, restalled TC, Spohn SFCs).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

just doing the bowls is pocket porting. Doing the SA stuff is polishing. Its not a full port unless you gasket match and TAKE OUT material in all the right places. So you will do polishing and pocket porting and maybe gasket matching.

 

five7 i think you worry too much. i'd have to agree with what you say, to me ported is reshaped, enlarged, and flow matched.

------------------
ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

Does porting really do that much to the performance of the engine??
I mean for example my L69, what would porting do HP wise to it??

 

First of all it's possible to have too much head. Not really a factor in your case.

The purpose of full porting is to increase the air flow into the engine and give it a straighter path into the combustion chamber. The exhaust ports are enlarged and polished to help the exhaust gases escape with little resistance.

When you port the intakes, you're removing metal so that the air fuel mixture has a straight path through the head. Since the engine is an air pump, it's possible to have too large a passage and not enough air fuel can be pulled into the cylinder.

By cutting down the short turn radius, trimming the walls, floor and roof of the passage down and doing a pocket port you're offering a better path for the air to follow as well as more air. You don't want to polish the intake ports as you need the roughness to keep the fuel in suspension from some turbulance.

I've seen extreme engines go to extreme when porting. The head bolts can be in the way of getting good flow. Porting is done completely around them then an insert is reinstalled for the head bolt to pass through.

Anytime you get aggressive with more than a simple pocket port you can consider the heads ported. There's many stages of porting though depending on how much metal is removed.

------------------
Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block (times are for the current engine)

Best ET on a time slip: 11.447 altitude corrected to 10.99
Best MPH on a time slip: 119.42 altitude corrected to 124.86
Altitude corrected rear wheel HP: 493
Best 60 foot: 1.586

Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

ede, it's not so much a matter of worrying, just like words to mean something. There's been a few posts in the past few days talking about "porting" stock L98 heads for a 400, "porting" stock van 350 heads for a performance engine, etc. I would think any amateur effort would produce less flow than most any bolt-on aftermarket performance replacement head.

"Pocket porting" and "bowl clean-up" are somewhat ill-defined as well. Does that include reducing the valve guides? Does it include smoothing machined-to-cast transitions? Who decides?

The tech article "Daniel Burk's Guide to Porting 305 Heads" is almost identical to SA's guidelines. Perhaps Stephen put it best by saying there are different stages of porting.

FWIW, I spent two hours practicing on one cylinder of a stock 305 head. Came out pretty good comparing my results to the pics in the instructions and the tech article. Then, 2 hours on the World heads gasket matching and blending into the port, cleaning up the entry (to 80 grit), and removing the perimeter bolt-type cover bosses (bye-bye warranty). The chambers will be a snap compared to the factory head. Maybe another 6-8 hours left, then cleaning and assembly.

Maybe I should change my sig to "SA'd World 305 heads"...