[F-BIRD'88]

You can make you own go no go gauges from sheet metal or welding rod to compare port width height dimensions by hand. Or use calipers. Just make then visually as close the same as practical.
Its the size of the "choke" that counts. (point of minimum cross sectional area)
Air flow gets real funky at supersonic speeds. Running Engines do not flow air like a flow bench.

[F-BIRD'88]

None of this general porting on this stock SBC head requires a flow bench. You got to put some air in a tire first before messing with the tire gauge.
A picture says a 1000 words.
http://www.hotrodders.com/forum/atta...0&d=1347916622

i did not do this head. Buts a really good pic of the desired finished form. Look at the chamber too.

[ChevroletSS]

Thanks for the info. Greatly appreciate it. Can you point me in the right direction on some bits to use for porting. All I have is the port and polish kit from jegs which is ok but not efficient. I need something about six inches long id say and one maybe three inches long. A good carbide bit I guess. What do you suggest

[F-BIRD'88]

get these two with a 6" shaft




2.5" shaft for this one

[1Gary]

Originally Posted by F-BIRD'88

None of this general porting on this stock SBC head requires a flow bench. You got to put some air in a tire first before messing with the tire gauge.
A picture says a 1000 words.
http://www.hotrodders.com/forum/atta...0&d=1347916622

i did not do this head. Buts a really good pic of the desired finished form. Look at the chamber too.

Congratulations,you have just discredited the whole foundation the aftermarket bases it's self on.......................

Now that just doesn't make any sense.

[F-BIRD'88]

The whole purpose of marketing and advertising is to separate you from your money in exchange
for what ever is being offered by the advertiser. And convince you that you need it.
And they will go to what ever lengths thats nessessary to "tell you what you want to hear", to get the sale.

[1Gary]

We all know as casted OEM heads are all the same.Right??. I'm call it BS. So to follow the same pattern reaps the same results without a flow bench to check if your just hacking away at a pc of metal or really doing better or worst. Taking tech back to what amounts to caveman times is illogical.

The first set of heads done right usually the response is OH!!!. That's what I have been missing..........

[vinniekq2]

1gary,do you have any experience with super stock engines? How do you measure cfm flow on stock castings

[ChevroletSS]

Hey F-Bird check out these bits. will these work ok. They are similar to what you have below.

I guess these are made for cast iron??? I have no idea.
http://www.goodson.com/5_Pc_Set_of_L..._Rotary_Files/

[oldbogie]

Originally Posted by ChevroletSS

Hey F-Bird check out these bits. will these work ok. They are similar to what you have below.

I guess these are made for cast iron??? I have no idea.
GOODSON : Engine Building Tools and Supplies

Check this out >>> GOODSON : Porting & Polishing : Rotary Files <<< it shows the difference between rotary files for iron versus aluminum. Iron uses a finer flute than those for aluminum. This is because aluminum melts into the clearance between flutes plugging and gumming them up till they won't cut. Iron just makes solid chips that fly off the cutting face.

You can use a coarse aluminum bit on iron all that will happen is a rougher surface finish from some chatter the wider flutes create, but they'll cut just fine. Aluminum will gum up the smoother fine iron flute almost instantly. You can kind of get away with the fine flute on aluminum if you frequently run the bit into a piece of bar bath soap. This lubricates the flutes preventing the aluminum from sticking. Same thing if you're cutting aluminum with a rotary stone or drum sander, run the stone or drum sander into piece of bar soap every few cuts and it'll stay pretty clean of imbedded aluminum. This of course leaves your bits and stones smelling clean and refreshing.

Bogie

[F-BIRD'88]

Goodson is nice stuff.

you only really need two of them with a long 6" shaft for this SBC head porting job.
LFR-34C and LFR-46C

Yes these Double cut style are for cast iron. Not good on alumunum.
Use single cut for aluminum.

There are other sources that are a little less pricey.
But avoid cheap chinese junk.

Welding supply and industrial tool supply stores usually have all this stuff.

google search carbide burr The same onces but with a 3/8" cutting head diameter are about half the price.

I use the various shaped mounted stones to shape the short side radius. The amount of material that needs to be removed is not that much to shape the short side. radius.
You don't need to run these at 10,000 rpm.

Ebay: remember good quality tools are not sold for dirt cheap. Can be real hit and miss.