[zildjian4life218]

Hey Everyone. I have a set of '882's from a 350 that I figured would be a good set of heads to start grinding away on. I am gonna work on the short side radius, bowl blend, gasket match the intake, and tear drop the valve guide boss. Here are some pics of where I am at now. All criticism is accepted!













I will post more as I progress.

[automotive breath]

One of the most important things to learn about porting is to size the bowl
and throat. If you look at this picture there is a margin left just after the
valve seat in the 12 o clock to the 4 o clock position. After that material was
removed almost to the seat. The margin should extend all the way around
the throat, the throat should be ~87% of the valve diameter.

[TTFiveOhRanger]

Look like a good start! Just don't damage something important and try to keep them all as similar as you can. Look up pictures from people who have hit the water jacket on that head and make sure you leave plenty of material there...

[zildjian4life218]

Thanks automotive breath. I will go around and clean that area up so its more even. I will also go in with a dial caliper and make sure I stay under 87% of the valve size.

[F-BIRD'88]

You want to carve two strong airflow flow paths around the guide boss.
With a bias on the common wall side.
Raise the roof of the port from the entry all the way to the bowl guide boss zone. Do not lower the floor of the port other than to clean up the rough cast. Open up the pushrod pinch width. Port match the entry to a felpro 1205 gasket.

This is a pic of a finished 305 head but the job is the same.

[automotive breath]

Listen to what f-bird is saying, there is not enough good information
written about shaping the area at the guide.

Here's a picture of a set of heads I'm using a snap gauge to begin to size the
bowls. Notice how I left plenty of material between the throat and the seat,
in your picture you already cut too much here.

[zildjian4life218]

F-bird - wow nice job on those guides. I will do as you showed on yours and make the two paths next to the guide where the air can flow. I will also get a set of the 1205 fel pro intake gaskets. I can't believe how much bigger the ports are on those gaskets. Is that a pic of those 416 heads?

Originally Posted by automotive breath

in your picture you already cut too much here.

I will make sure to be more careful in this area. I checked with a caliper and im at about 88%-89% now. I will buy an inside telescoping gauge so I can measure it more accurately.

[automotive breath]

Originally Posted by zildjian4life218

I will make sure to be more careful in this area. I checked with a caliper and
im at about 88%-89% now. I will buy an inside telescoping gauge so I can
measure it more accurately.

Think of it this way, its easy to remove more material, difficult to put it back.
With that in mind target something smaller than what you want to end up with
like 85% at the throat and 92% in the bowl.

What you are doing is sizing and shaping an orifice, preparing the air to flow
around the valve, the primary restriction in the port. This is the most
important thing to learn about porting.

Next concentrate on the push rod pinch and the short turn.

[zildjian4life218]

When shaping the valve guide area how much material should I leave around the valve guides? They are bronze I imagine there is a certain amount that should remain there.

[454C10]

good job.

the bowl smoothing is the best back for the buck. I would stop there, as the other stuff doesn't add nearly as much.

[ap72]

the object isn't to take out as much material as possible, but to smooth what is there. You don't need to grind on every surface, you already went to deep on most of it. Use the carbide bit to take off the big deges and use a 60 grit cartridge roll to bring it all together. When you're starting out less is more.

[zildjian4life218]

Originally Posted by ap72

the object isn't to take out as much material as possible, but to smooth what is there. You don't need to grind on every surface, you already went to deep on most of it. Use the carbide bit to take off the big deges and use a 60 grit cartridge roll to bring it all together. When you're starting out less is more.

yea my bad I got a little too happy with the grinder.

[454C10]

read this.

http://www.chevyhiperformance.com/te...ing/index.html

[zildjian4life218]

Originally Posted by 454C10

read this.

http://www.chevyhiperformance.com/te...ing/index.html

thats a good article. bookmarked it

[ap72]

Originally Posted by zildjian4life218

yea my bad I got a little too happy with the grinder.

hey, you're working on 882 heads, its not like you made them any worse.

If you want you can also try your hand at epoxy, on race heads its common to use epoxy to fill in certian areas, you need to use the right kind of epoxy and sealant but you could try it.