Sitting Bull

OK, everyone! The dreaded moment has arrived ... it is time to publish or perish

Here are some pictures of my bare heads, and the tools to be used to turn them into rip-snortin' Vortec eaters

No kidding, when you are done following the instructions in this thread, your 305 heads WILL flow as well as the fabled Vortecs--if not better!!!

And all for no more than $400 US--including all new valves, springs, seals, the WORKS

First, the bare head. It is a "601" casting. But the 081 and 416 castings are great, too. Some say even better. These are the last three digits of the casting number, found on top of the head.

The only 305 heads you MUST avoid are any that come on a TBI engine--they have insurmountable casting flaws :nono:

And by the way, YOU CAN DO THIS WORK YOURSELF! This banged up ol' prairie boy did it with some serious health problems, so even the ladies should NOT consider this outside their abilities. Physical strength has almost nothing to do with this. In fact, women can probably do it better than us guys because you are more detail oriented :hail:

Sitting Bull

Next, the most useful tool in my inventory--a bigger hammer!

Just kidding

an intake and exhaust valve to plug the holes when polishing the combustion chambers.

Sitting Bull

The other head, on the floor, along with the 32,000 rpm electric die grinder and also my homemade rpm controller (on the floor, too), which I thank F-Bird'88 for. Plus the Standard Abrasives deluxe porting kit.

The die grinder is costing me $48/week to rent. (Unless otherwise noted, all currency is in Canadian dollars. To approximate US dollars just knock a third off.)

The SA kit was $104. But you DON'T need it. The carbide cutters are all you need.

The rpm controller cost $30 to build.

Download the Standard Abrasives head porting guide here: http://www.sa-motorsports.com/portdiy/diyport.pdf

It is for 305 heads, happily enough

Sitting Bull

A couple close up shots of the intake ports. Kinda rough, eh?

Sitting Bull

The other end

Believe it or not, the openings fit the gasket extremely well. There is only a minimal amount of enlarging to be done at the top left and right of the intake ports, maybe 1/8 to 1/16 of an inch.

The bottoms are a perfect fit.

FastElectrics

where did you get your porting kit from? since I see we are in the same country.

Blackened

You're not done right ? I don't see what the difference is from the stock ports ..... ?

F-BIRD'88

Going to need some carbide cutting bits too.
There is about 4 that I use.
1 shaped like a christmas tree
1 shaped fatter like a cylinder
1 sharp cone shaped
1 6" long shaft flame shaped cutter for deep inside the intake port.
You can get them from Snap- On or industrial supply
stores ( welding) Boc Gases has them sometimes.
There is too much metal that has to be removed to do it all with sanding rolls and a few stones. I use those last.
Most of my work is done with the cutters.
Yu'll need some SAFTEY GLASSES too. Not worth loosing an eye over. You can buy roll pins at the hardware store
and drill and pin the studs. ( be patient and run the drill at
moderate speed cause the studs are case hardened.
The cast iron is easy to drill thou. Use your drum shaped stone to sharpen the drill bits.) The easiest way to quicly shorten the guide boss in the bowl is with a drum shaped stone with a concave end. You use the fat shaped cylinder shaped cutter the most, followed by the flame shaped one.
You don't have to run the dye grinder at 20,000000 rpm
just a good fast speed. Wear work gloves as the vibrations
will bug your hands after a while. I like to do this outside when the weather is good. Good lighting is important, plus it makes a mess.
Both pairs of my heads are at the machine shop waiting for their valve job so no pics yet.

Sitting Bull

Outboard Rebore, Inc.
Hwy 1 East & P.R. 207 Deacon's Corner
Winnipeg, MB R3C 4B3
Phone: 204 222-3782
Phone: 888 376-7359
Fax: 204 224-2826
www.outboardrebore.com

I called the 1-888 number and got it two days later through Purolator.

Deluxe Porting Kit Part No. 260001

Sitting Bull

No, no ... you silly boy

Just establishing a starting point from which to gauge my progress

Sitting Bull

Here are the two extra carbide cutters I bought for $13 apiece. Are these what you meant, F-Bird'88?

Sitting Bull

Here is what the ports look like after scribing in the gasket matching.

Christos

Very cool!

Are you going to do some sort of flow-testing and/or dyno with before-after specs, so we could know the soild gains?

Thanks for the pictures, this will be a fun thread to follow!

johnsjj2

You are using a better tool than I did. I used a die grinder. It got real hot, and oily from the air tool oil I kept using. The electric ones keep the cutting tool more stable. You would be surprised how fast you can bend a carbide cutter if it bounces once. After that they get all out of balance. I am glad to see you are using an electric one. Here are some pics of what little I did to my heads.

johnsjj2

One more:

Sitting Bull

We are doing these heads to F-Bird'88s specs, as close as we can anyway. He has flow comprehensive flowbench numbers, maybe he'll post them here for you.

Basically, they will flow as well or better than a set of L31 Vortecs

Sitting Bull

OK, here's a picture of a finished gasket matched port. I didn't take anything much off the floor but took a fair amount off both sides and the top. I used the flame shaped carbide tip.

Any advice on these pics, Russel? Are the walls too smooth?

It is interesting that there is a casting seam about halfway down each port, that runs right through the entire head.

Sitting Bull

Here is another angle. I've only managecd to do one head so far.

Does anyone know why there is a cavity in the roof of the intake ports, right below where the rocker studs are? The arrows point to it, though the pic isn't too clear. (The head is upside down in the pic.) Every intake port has them and they are a fair size

Sitting Bull

Here are the combustion chambers. They have these sunken indents where the arrow points. Is this typical? Do I have to grind these out or just leave them alone?

I would think grinding them out would increase the combustion chamber size kind of radically.

And there is an opening in the casting where the other arrow points, which is near the heat riser port. Is this also normal?

My hands are tingling like crazy from doing this grinding. The die grinder leaves your hands almost feeling numb after a couple of hours. Your hands feel like when you hit your funny bone. That was about all I could take of it tonight

Sitting Bull

Is that a Vortec head? It has quite a bump where the plug enters the chamber. Seems odd for a Vortec. (It sure ain't a 305 head, what with that kidney shaped combustion chamber.)

I can't believe how numb your hands get from doing this, even wearing gloves.

Did you notice a hp difference after your head job?

F-BIRD'88

They'd be the ones... I use the fat cylinder shaped one a lot
Mine also don't have a sharp point like yours.

F-BIRD'88

Have a good look at those Vortec head's combustion chamber.
Notice how the intake valve is unshrouded around its circumfrence. You can't unshroud the valve quite to much on a 305 head but you can do some. Watch how much you
widen the chamber if the head is going on a 305. You don't want it wider than the bore. Get a 1.94 valve and just lay back the chamber till it slides in the guide without hitting the chamber.
The area of the chamber wall within 5/8" of the spark plug hole and towards the intake valve needs to be layed back and unshrouded with a nice big radius to the roof of the chamber
like the vortecs. Slide a valve in and imagine you were a liquid trying to sneek into the chamber at low valve lift.
If you spray water through the ports with the garden hose you can see how the air flows along the long common wall and roof,
past the valve guide and swirls toward the center of the chamber
as it exits the port. This is the area that porting will give the most gain. You want to straighten the common wall, widen the roof area between the wall and guide as you approach the bowl.
Thin and trim down the guide. Don't be shy here, this is a major flow area. The only thin area is right where the port wall passes the head bolt between the ports. If you do bust through there u can epoxy it up.

F-BIRD'88

See the D shaped water passage between the intakes
on the deck... imagine a two lines draw'n from the center of the two intake guides, intersecting at the center point of the back of the D. Where those lines cross the chamber edge is a weak
area (crack prone) be carfull how much you unshroud for the valve here.
Se how there is a little boss (raised circle) around the spark plug hole in the chamber. DO NOT grind this out. All you'll do is expose
the threads of the sparkplug in the chamber and create a possible hot spot. Cleanup and polishing is all that is nessessary in most of the chamber. The indent cast in the chamber does not need to be ground out either.

Sitting Bull

Wow!

After turning the heads over I see that these valve guides hardly intrude into the bowls at all. It seems to me that every other picture I've seen of valve guides shows them being much longer than mine.

Does it look like these guides have already been worked over?

There is also an insert inside every one of them, which leaves very little meat surrounding them. Is this normal or what gives?

Really, there is next to nothing to work with here. Are they good the way they sit???

On the exhaust guide's port side there is sufficient material to shape and remove to increase flow, but on the back side of the guide it is almost flush.

Sitting Bull

Here is another view. The guides are just sort of a dimple/bump, really

And another question: These combustion chambers don't have the typical squared off D shape that other 305 heads have. They are rather more eliptical than D shaped, and VERY different than any other 305 head I've seen. They almost look like the Vortec chambers. All they are missing is the widow's peak dipping down between the valves, on the opposite side of the spark plug. Has anyone else seen these shapes of combustion chambers on a 305 before???

Their casting number is 14022801 which Mortec tells me is from the 1980-86 Chevy 305. (The other says 14022601.) Is this some sort of high performance head? Or maybe low performance?

Sitting Bull

Arrow 1 shows the funny cavity under the rocker stud. Has anyone else come across these in their 305 castings? Do you think they will disrupt air flow into the chambers?

(I understand from the latest Super Chevy mag that even the new Vortecs have this hole beneath their rocker studs. They tested a set that they also filled in but it didn't improve the flow any.)

Arrow 2 shows a small bump in the casting. On some of the intake runners it is really non-existant. Is it necessary to grind these out? They would be a real pain to get at with the grinder, as the quarters are too small, IMHO, to even get the tip in there.

Arrow 3 shows what looks like previous machine work done on the bowls. Is this done at the factory or is this something someone else has already done to the bowls?

Sitting Bull

Here is a "standard" D shaped 305 combustion chamber for reference sake. Quite different, isn't it?

My combustion chambers are much more tightly shaped around the exhaust valve. Therefore, it would seem to me that my chambers would be fewer CCs in size than the "normal" ones. Yes??? No???

Sitting Bull

These must be awfully hard questions

I almost get the feeling that I'm into territory with this porting that very few other people on this board have ever gone through.

Come on gang! Any answers???

F-BIRD'88

1> Don't bother filling it in. Not much flow here.
2.Yes grind out those bumps in the port roof and floor.
3. Yes thats the marks left from the factory bowl cutter.

Sitting Bull

Alrighty then! Let's look at todays efforts.

Here is a polished exhaust port. I have only used ONE of the cutting tips that I bought, the flame sorta shaped one. I don't know whether the port must be more highly polished or not. Any input?

I couldn't reach the valve guide boss very well, so I'll have to get a different tip to do it with.

Sitting Bull

Here you can see my bowl blending efforts. This is hard to do with the cutter I have. I need one the same shape but rounded on the end. I'll grab one tomorrow.

This is very hard to get a decent picture of.

I am simply trying to form the bowls into one continuous and smooth whole. I'm also grinding a fair bit of material away in doing this. Most is coming from beneath the valve seats, as I'm blending into the floor.

Is this correct?

Sitting Bull

This intake port shot shows the surface finish that every thing is turning out like. Is this smooth enough for for EVERYTHING, or do the exhaust ports have to be shinier, like chrome?

Sitting Bull

OK, I have smoothed out almost everything in the ports but these last little bumps, which are very minor, are a real pain to get at. But I'll try and get 'em

I'm basically trying to transition all the edges of the bowls into one smooth, sorta round, surface. Some of this really requires a lot of removal. Is this typical???

egmonster

I am inexperienced at cylinder head porting (never done it before!) but I am curious as to what exactly you're doing. It seems to me that you are going to be hurting your compression with all the material you remove from the chamber yes?

Sitting Bull

No, I haven't even touched the combustion chambers yet

Everything done has been before the intake valve and after the exhaust valve.

All I plan on doing to the chambers is to polish the surface and deshroud a little bit near the intake valve.

egmonster

Ahh oh ok. I'm currently porting my baseplate and polishing my plenum and what not and I was tempted to look into head porting as well... The motor I have needs a rebuild though so I'm not sure it's worth doing anyway. Going to buy a new engine next summer... just fixing up and doing what I can with what I got. Always good to know these kinds of things though .

Sitting Bull

Cool! Post some pics for us to see your handiwork. I'm sure there are some guys (or girls) wanting to do the same thing. It'll encourage them to be as adventurous about doing things with their own two hands as you are :hail: :hail: :hail:

NTChrist

HEY! We're both working on Black and Decker Workmates. Doesn't it suck to not have a proper-sized workbench?

As for the intake ports, you can polish them as much as a 50 grit will get them polished (not very shiny). Don't rely on the casting bumpy-ness of the head to keep the fuel in suspension. A 50 grit sandpaper roll will do that job fine.
Yes, you're right, get the exhaust port as shiny as possible. Like chrome. Not only will it help the airflow, but more importantly, it will make it harder for carbon to stick to the walls. Carbon build up is bad for flow.

As for where your specific head casting came from, are they the heads off of an LG4? I have the 416's, which would be the other 305 head from 80-86. I was told the 416's were the heads with the most potential (sorry), and went on the "H.O." designated engines. This makes me think you have the LG4 heads. Unless the LG4's came with 416's, too. I'm sure F-BIRD'88 knows, he knows everything about small block chevy heads. Actually, now that I've got you buttered up, F-BIRD, you live in St. Catherine's right? I'm moving there in a little over a month for school. Would you mind if I had you take a quick look at my heads, maybe suggest a few things I could fix? Like in a month, or so. I can pay for the help with beer!

Sitting Bull

You are shameless, NT

I like working at them on the Workmate. It lets me sit down while doing the work. (Bad back.)

My work on the heads currently has about the same finish as most after market heads seem to sport. More or less that CNC machined kind of look. I'm tempted to leave them as they are. If that is good enough for Dart and other top end heads, why wouldn't it be good enough for me? Maybe I am just getting lazy but I don't think much carbon could stick to that surface anymore.

I also looked at the recent head porting articles in Car Craft and Chevy High Performance and they left their heads with the same sort of fine carbide cutter finish. In fact, Car Craft said that their gurus let them leave their own heads "de-chromed" on the exhaust port but will highly polish the customer's sets simply because most customers think that how they are supposed to look. Boudary air flow physics and such.

What do you make of that?

I got these heads from Apeiron and Teal Shark. They were on a high performance 350 at one time and also on a turboed small block. Apeiron thought they were 601 castings but one turned out to be, upon closer inspection of the casting number, an 801. Go figure.

Anyway, the combustion chambers look much more like the high performance kidney shape of the Vortecs than they do the 416's D shape. Strange but no one seems to have a definitive answer on this yet. I think heads are more of a black art, than a science, you know?

F-BIRD'88

DID someone say BEER!!!:lala: :lala:

Guest

Surface finish is the final touch on that last little bit of flow, prevention of reversion, and fuel suspension. Theres more involved in that than anyone could teach you by making a few statements and for the most part its above what most of us can do and make work properly. It takes experience and lots of testing. I couldnt even begin to attempt what some of those guys do. But in short, yea ports that are not smooth and shiny and have the correctly grooved, ribbed, dimpled surface is better if its done right. And like he said, most customers would see that and think the heads were left unfinished when in fact they were probably better that way.

I could take a set of heads I worked on as an example, I'll have to post a pic later. Basically theres a spot in the chamber that is totally clean of carbon, its where the fuel is sticking to the chamber wall. That area I need to take the polish off and put some nice grooves in perpendicular to the airflow path at that point. I wouldnt have known this and didnt know this until I took the heads off the car with 8,000 miles of use on them. I even put them back on the car and didnt realize until later and looking at the pics that I should have done something in that area. Thats where experience counts.

Sitting Bull

madmax,

Man, you have GOT to post that picture right away! I'm going to be finished these heads by tomorrow, if all goes well, and I want to see what you are talking about. I'm just about to start on the chambers.

F-BIRD'88

NTCHRIST:
I don't live in St Kitts ,but am real close.
Are you going to Brock U, or Niagara Coll. in the Fall.?
I don't know everything about SBC heads, By a long-shot. Trust me. I learn more every day. I've never actually eyeballed
those "801" castings before. Thet look like "601's" but even more "closechambered". I would CC them to find out the actual chamber size. They look smaller than the 55/58cc of the 416's.
They should turn out well, but may need some more chamber work to unshroud 'em especially from the plug to 5/8" toward the intake valve. This is where the flow wants to swirl out of the port into the chamber toward the center of the chamber.
You want to remove all the rough is cast surface but like MadMax
stated you do not want a smooth polished finish at all in the intake port.

Yes, removing material from the chamber will increase the volume. But if done right, will increase flow and power. You can CC the heads after you're done and then have them surface milled to restore the original volume or to increase the CR.
Sitting Bull :Looksa like some one did some valve guide repair on thise heads before. You should still streamline and shorten the guides though. You're going to have trouble removing those bumps in the roof of the port using a pointed cutter.
The one I use the most is a fatter, cylinder shaped cutter with a rounded head. also one with a 6" shaft that will reach all the way in from the intake flange opening to raise and contour the roof of the port. I use these to hog out the bowl and carve a flow path from the common wall/ roof, past the guide
and into the bowl. It chews out material quicker and is the right shape. The pointed ones are used to square up and sharpen up the corners of the port opening at the intake flange.
A ball shaped stone is nice for radiusing the shortside from the
valve seat to around to the floor of the port.
A cone shaped cutter with a rounded nose is good for carving two flow paths around the guide in the exhaust port. This is where most of the material needs to be removed. Huge exhaust port exits are not nesssessary and will just make your headers leak.

Sitting Bull

F-Bird'88,

How much did you enlarge the exhaust ports? As large as the gaskets or smaller?

Do you think that it is really necessary to enlarge the exhaust valve to 1.60" or will the 1.50" size be OK?

F-BIRD'88

You want the exhaust port opening to match the header opening
not the gasket. On the typical small street header that means
a 1.5 to 1.625 opening tops. Corner to corner. I only open mine a minimal amount here.
The first set of heads I did I used 1.6 valves.
I have two more sets waiting for valve jobs now. One is getting 1.5's, one is getting 1.6's. I'll let you know the results.
I think it really depends on your wallet wether you should use
your old 1.5" valves over.

The one set i have, already had 1.94 and 1.6 vales installed
so I just ported 'em up and pinned the studs. The other set was all stock so I ordered 1.94 intakes and I got lots of good used 1.5" valves laying around.

My friend ( Owns a machine shop/speed shop) is doing the valve work and surfacing, but I'm not a top priority cause he has to do it cheap for me. LOL. By the time he's done he'll probabily
have his new flow bench so I get 'em flowed too.
(another freebe,,,, he ows me.)

Sitting Bull

OK, thanks for the answers.

Here are the two tips I picked up this afternoon. I took back that totally pointed one, it was totally useless for this work

It's funny, but these are exactly the ones you told me to get. Deja Vu all over again, eh?

I don't have any valves at all for these heads, so do you think I ought to go the 1.6 route or just stick with the 1.5s?

When you say "corner to corner" on the exhaust port you mean diagonally, right?

And do you think the cutter finish is good enough for the exhaust port?

NTChrist

F-BIRD'88: I'm going to Brock for next year. It'll be my second year in University, my first year back in Canada.
I'll drop you a PM when I'm in town, maybe we can get together, talk cars, I'll bring the beer, etc.

Sitting Bull: I would take Mad Max's and F-BIRD's advice before I take mine.
My assumption was that limiting carbon in the exhaust area was a good idea. Pretty much everything I read said that the exhaust should be polished, and the intake should be scuffed. Of course, some of the things I read also said to grind the valve guide level with the port roof. Sounds like a bad idea to me, so I'm guessing the cliche of "Don't belive everything you read" applies here.

F-BIRD'88

Sitting Bull : that long cutter is perfect. they cost more with the long shaft but hey that racing.
Run it slow and keep it pressed to a wall till you learn how to control it. They tend to chatter in the port more till you get the really rough cast surface cut off.
If it starts to vibrate, the shaft has bent slightly because of a chatter. Just hold it against the wall deep in the port and
run the die grinder and it will tend to rebalance itself.
Be sure it is pushed all the way into the die grinder chuck.
Try using it with a electric drill first to get used to it. It will still cut pretty fast even at the slower drill speed.
I also use a little thicker cylindrical shaped 4" shaft cutter with a round end. for the bowl and port walls.

NTCHRIST: cool.... Labatts Blue....

Sitting Bull

I put the long cutter in and spun it up, just for kicks. It goes into a wobble mode for a second ot two as it spins up but after that seems fine. Around $17 Canadian at Acklands.

The stone for the chambers was only $1.66

Do you mean hold the shaft against the port wall until the vibration goes away?

RB83L69

Looks good...

The single biggest improvement you can make for flow is the short side radius, especially the exhaust. The shot through teh exh port with the light under the chamber shows that most of the step from the factory bowl cut is gone. Patience and care in that area will reward you.

Looks like those have had the bronze guide inserts installed at one time or another, and whoever did it milled the guides down almost flat.

The seats have been replaced, which is good for longevity but leaves that terrible ring around them where the seat meets the casting. Definitely try to clean as much as possible of that up.

Undercut valves make a big difference: in some castings, 1.94" undercut valves will flow more than straight 2.02" ones.

Note how both the intake and exhaust valves almost scrape the side of the chamber, at all lifts below .200" or so. Typical 305 chamber shrouding. Open that area up so that there's clearance between the valve and the chamber surface.

Get rid of the whole sharp edge around the chamber where it meets the deck. That edge is one of the main causes of detonation.

See how the bowl area looks almost like a cylinder perpendicular to the deck, and the port looks like a rectangle parallel to the deck, where they meet. There is a major discontinuity there in most heads, those seem to have it worse than usual. It shows up especially well in the pics with the numbers drawn on it. smooth that out as much as possible, without enlarging it any more than necesary.

IMHO gasket matching is the least important part of the job except for the really huge intrusions into the intake port (like perimeter valve cover bolt hole bosses often create), and should be done last.

This is how you get as close to "free" horsepower as you'll ever find!! Good job so far, don't get too eager and hit water or push rods or head bolts. When you're done, get them machined for 1.45" springs, and you'll be ready for a high lift cam, you may even have a stock screamer.