[loli]

Be sure to wear a dust mask or respirator. I had a pair of heads boiled in cleaner once before I ported them and lost my voice for two days from breathing the acid dust.

[Camaro_Nut2001]

Originally Posted by loli

Be sure to wear a dust mask or respirator. I had a pair of heads boiled in cleaner once before I ported them and lost my voice for two days from breathing the acid dust.

Yep, I wear a resp. and use my shop vac. Welcome to our Wonderful community!!

[Camaro_Nut2001]

I got the guide bosses cut down and shaped as close as I could to the pictures in Vizards book. These pictures don't show the shape very good but they come to a point on the top of the guide and taper down. I'm kinda skittish on taking anymore out. Do ya'll think I should leave the intake ports alone or port them as well? Also, finished all the guides on this head. From the pictures it looks like I cut the spring seats but I just skimmed the top to knock the varnish/dirt off. Please let me know what ya'll think not only about the intake ports but all the stuff I have done thus far. I plan to either start pulling and taping the studs tomorrow or, if ya'll think I need to port the intakes or any other stuff, i'll do that. I do know i'm really enjoying this, lol. Here are the pictures
http://www.hotrodders.com/forum/atta...1&d=1357282581
http://www.hotrodders.com/forum/atta...1&d=1357282581
http://www.hotrodders.com/forum/atta...1&d=1357282581
http://www.hotrodders.com/forum/atta...1&d=1357282581
http://www.hotrodders.com/forum/atta...1&d=1357282581

[F-BIRD'88]

What is the date code on your vortec heads. It's stamped on the exhaust side flange, on a machined surface area.
I don't have any pics of my ported vortec heads. I did them quit a while ago. They are on my 406.
2.02x1.60. I never took any pics of those.
With the stock 1.94" valve intake port you are best to just smooth and generally clean up, whats there.
The form under the valve is quite good. At least on the early Canadian made heads. 1996-2000.

The later mexico heads are smaller, low less in stock form and can use dome more work.
How you port thee heads is dependant on how they are going to be used.
The port shape you want for a big cam big valve lft "race" is different than the port and bowl shape thats best when the valve stays relativily close to the seat. small moderate duration and lift.

The vortec head has really good low lift flow in stock form. for a mild mtor do no remove the critcal funnel shape of the bowl under the valve job.
You can generally streamline the guide boss so air can go around it.
Flowing the garden hose thru the port will help you see the natural flow path on a SBC head.

Post all the stamped numbers that are stamped on your heads. May need a light and some emery paper to see them.
On the exhaust flange.

[F-BIRD'88]

When I did a mild clean up on a previous set of vortecs with stock valves.
The flow was 228cfm . Got it to 232 some odd with a general but mild bowl clean up.
I was not looking for or after a big gain. Wanted to evaluate them in stock form and the cam used was only .442" lift.
Use common sense here. The as cast shape is quite good as is. Especially for mild camed motors.

If when you go to a larger 2.02 or 2.05" valve and the cam gets a lot bigger you can open up the port and bowl more to good effect.

You can be quite agreeive on the exhaust side porting but do not make the exit huge.

[F-BIRD'88]

Do a google image search using the term meaux and porting and vortec and other relevent search terms.

Refers to Larry Meaux

MaxRaceSoftware

[Camaro_Nut2001]

Originally Posted by F-BIRD'88

What is the date code on your vortec heads. It's stamped on the exhaust side flange, on a machined surface area.
I don't have any pics of my ported vortec heads. I did them quit a while ago. They are on my 406.
2.02x1.60. I never took any pics of those.
With the stock 1.94" valve intake port you are best to just smooth and generally clean up, whats there.
The form under the valve is quite good. At least on the early Canadian made heads. 1996-2000.

The later mexico heads are smaller, low less in stock form and can use dome more work.
How you port thee heads is dependant on how they are going to be used.
The port shape you want for a big cam big valve lft "race" is different than the port and bowl shape thats best when the valve stays relativily close to the seat. small moderate duration and lift.

The vortec head has really good low lift flow in stock form. for a mild mtor do no remove the critcal funnel shape of the bowl under the valve job.
You can generally streamline the guide boss so air can go around it.
Flowing the garden hose thru the port will help you see the natural flow path on a SBC head.

Post all the stamped numbers that are stamped on your heads. May need a light and some emery paper to see them.
On the exhaust flange.

I'll get those numbers today. I did buy a pair of "062" that came off a running 2000 Chevy truck for $125.00 the other day but these i'm playin with are not them. By looking at what i've done on the exhaust in the pictures do you think I have improved them? By lookin at em and imagining(sp) in my mind the air flowing thru them I feel i've helped them but I would like your opinion. I will post the numbers a little later.

[hcompton]

Originally Posted by Camaro_Nut2001

I'll get those numbers today. I did buy a pair of "062" that came off a running 2000 Chevy truck for $125.00 the other day but these i'm playin with are not them. By looking at what i've done on the exhaust in the pictures do you think I have improved them? By lookin at em and imagining(sp) in my mind the air flowing thru them I feel i've helped them but I would like your opinion. I will post the numbers a little later.

They are not all the same but an improvement. They should flow well with a little more tweaking. Final cuts are slow and steady. If your tired same them for the next day.

Intakes are probably good for what they are. I would take off the ruff casting maybe even just use sand paper rolls for the intake side. The guide on the intake side are pretty tall. They could be cut but they will probably only be worth a few ponies and could result in bad flow if not done correctly.

Are these your heads your going to run or a set you are using to learn on. If its for learning purposes or all out racing. You can cut the guiide all the way put and leave a flush surface. I would think this should flow the best since these are not swirl port heads and rely on the combustion chamber to turn the air inside the combustion chamber and allow for the final mixing of the air as it flows past the valve and swirls into the port. But this type of short valve guide will crap out the seals and get wobbly real quick unless real guides are put in place first. But it will last 20k miles or a race season. I also thin the valve stems on the lathe to allow for more flow. Just dont do this with sodium filled valves. And back cut the seat area of the valve right down to the seat and allow for better flow over the valve. For bike race engines i will even round the seats with the flapper leaving the valve flat and rpunding the seat in the head and lap the valves in to seat them. Give a lot better flow at low lift levels that will allow the engine to get more air moving sooner in the intake cycle.

Valve size is also usally only at the seat where is touches the head. So moving the seat right out to the edge of valve will increase the effective valve size. And allow more flow at first opening event which allows more air to flow across the entire intake cycle.

Sorry for the short discription it would take hours to go over everything but for your heads a basic clean up should be all that is needed.

Hope this helps.

[Camaro_Nut2001]

First off, Thank you for the great info. I ordered some longer mandrels, for the cartridge rolls, and they should be here today. I didn't get tired I just didn't want to take to much off the guides for fear of exactly what you said, weakening the guide. These are the heads I plan to run and I want them to last alot more than 20K miles. After looking at the pictures on the computer I did see where they are definately not the same. They look different just by lookin at them. I'm gonna get some numbers for FBird in a little bit and post them and i'll do a little "Tweaking" and try to get them as close to the same as possible. I don't have a way of cuttin the valves myself, although I have done it a few times on a schools machine, but I am gonna lap them in good. I "may" talk to my machine shop friend about what you suggested on cuttin the valves. There is a pretty big ridge under the intake seat, do I smooth it out and blend? I've read not to disturb it and also to smooth it out, lol.

Originally Posted by hcompton

They are not all the same but an improvement. They should flow well with a little more tweaking. Final cuts are slow and steady. If your tired same them for the next day.

Intakes are probably good for what they are. I would take off the ruff casting maybe even just use sand paper rolls for the intake side. The guide on the intake side are pretty tall. They could be cut but they will probably only be worth a few ponies and could result in bad flow if not done correctly.

Are these your heads your going to run or a set you are using to learn on. If its for learning purposes or all out racing. You can cut the guiide all the way put and leave a flush surface. I would think this should flow the best since these are not swirl port heads and rely on the combustion chamber to turn the air inside the combustion chamber and allow for the final mixing of the air as it flows past the valve and swirls into the port. But this type of short valve guide will crap out the seals and get wobbly real quick unless real guides are put in place first. But it will last 20k miles or a race season. I also thin the valve stems on the lathe to allow for more flow. Just dont do this with sodium filled valves. And back cut the seat area of the valve right down to the seat and allow for better flow over the valve. For bike race engines i will even round the seats with the flapper leaving the valve flat and rpunding the seat in the head and lap the valves in to seat them. Give a lot better flow at low lift levels that will allow the engine to get more air moving sooner in the intake cycle.

Valve size is also usally only at the seat where is touches the head. So moving the seat right out to the edge of valve will increase the effective valve size. And allow more flow at first opening event which allows more air to flow across the entire intake cycle.

Sorry for the short discription it would take hours to go over everything but for your heads a basic clean up should be all that is needed.

Hope this helps.

[Camaro_Nut2001]

Originally Posted by F-BIRD'88

What is the date code on your vortec heads. It's stamped on the exhaust side flange, on a machined surface area.
I don't have any pics of my ported vortec heads. I did them quit a while ago. They are on my 406.
2.02x1.60. I never took any pics of those.
With the stock 1.94" valve intake port you are best to just smooth and generally clean up, whats there.
The form under the valve is quite good. At least on the early Canadian made heads. 1996-2000.

The later mexico heads are smaller, low less in stock form and can use dome more work.
How you port thee heads is dependant on how they are going to be used.
The port shape you want for a big cam big valve lft "race" is different than the port and bowl shape thats best when the valve stays relativily close to the seat. small moderate duration and lift.

The vortec head has really good low lift flow in stock form. for a mild mtor do no remove the critcal funnel shape of the bowl under the valve job.
You can generally streamline the guide boss so air can go around it.
Flowing the garden hose thru the port will help you see the natural flow path on a SBC head.

Post all the stamped numbers that are stamped on your heads. May need a light and some emery paper to see them.
On the exhaust flange.

The numbers I found are: 10, 062, 8, 18, M127, GM-D, 12558062. Are these what you need?

[F-BIRD'88]

yup thanks

[vinniekq2]

all this porting is a great idea.Remember that almost all the heads need the most work on the exhaust side. Doesnt matter how much air goes in the intake side if it cannot leave

[hcompton]

Originally Posted by vinniekq2

all this porting is a great idea.Remember that almost all the heads need the most work on the exhaust side. Doesnt matter how much air goes in the intake side if it cannot leave

This is 100 percent true. Most factory heads work well because the intake side is under a lot pess pressure to pull the charge in than the exhuast side. The exhuast is going to come out. Because the piston is going to force it out. Most factory heads are very unbalaced because of this fact.

But with heads designed for efi you got to assume it is also built to run with little to no over lap. Now with a poor flowing exhuast port a larger cam with good overlap will not scavange like it is designed to so the exhuast ports always need attention first when starting with an efi head.

Most ford guys are amazed to see the exhuast bump in the 80s and 90s 5.0 engines. It blocks most of the port and by itself its worth 20 hp and will make sure any bolt on you install only works so well. This is also the reason some cars will respond to bolt ons and make 500hp and other will never pass the 300 mark.

On the intake side in this case i would think there isnt much power to be gained past the removing of the ruff casting surface to a smoother sanded surface.

Some none efi heads have the opposite problems. Balance is the key and getting the ports to flow enough to support the rpm the cam is requesting from the engine.

Just some general info to spur discussion.

[ap72]

Originally Posted by hcompton

This is 100 percent true. Most factory heads work well because the intake side is under a lot pess pressure to pull the charge in than the exhuast side. The exhuast is going to come out. Because the piston is going to force it out. Most factory heads are very unbalaced because of this fact.

But with heads designed for efi you got to assume it is also built to run with little to no over lap. Now with a poor flowing exhuast port a larger cam with good overlap will not scavange like it is designed to so the exhuast ports always need attention first when starting with an efi head.

Most ford guys are amazed to see the exhuast bump in the 80s and 90s 5.0 engines. It blocks most of the port and by itself its worth 20 hp and will make sure any bolt on you install only works so well. This is also the reason some cars will respond to bolt ons and make 500hp and other will never pass the 300 mark.

On the intake side in this case i would think there isnt much power to be gained past the removing of the ruff casting surface to a smoother sanded surface.

Some none efi heads have the opposite problems. Balance is the key and getting the ports to flow enough to support the rpm the cam is requesting from the engine.

Just some general info to spur discussion.

it's actually 100% wrong... a 5cfm gain on the intake is worth more than a 5cfm gain on the exhaust, even though the % difference is smaller.

Also, the Vortec intake tract is better than previous sbc heads, but the exhaust is NOT worse, its actaully a hair better too, just not as much as the intake. People get caught up in the intake/exhaust ratio and fail to see what they're really looking at on the exhaust side. Also, there's NO crossover, which is a pretty big deal compared to most other stock sbc heads.

[vinniekq2]

A really good example is porting on F E heads. want to wake up a 390,port the exhaust uncork the exhaust system.Old dodge sb...port exhaust side.
want to make power with vortec heads,open the exhaust.
best after market heads have a high exhaust ratio.
dont want to use a split duration cam or thumper cam,port the exhaust
how many high powered cars have small exhaust?