D0OE exhaust ports

[travis]

Looking for suggestions on what to do with the exhaust side of these heads. The exhaust guide boss is kind of ridiculous...very long and really covers up a good portion of the space between the guide and the inner wall. I’ve read that iron here is pretty this, so I will try to just cut the guide boss and leave that part of the bowl alone. The throat right above the top cut is 1.36”, with a 1.50” valve. The short turn has a sharp lip that I will fix. Anything else I should attempt?

Also...there are 2 lips on the short turn side as you can (hopefully) see. What is that? Does this mean it has had seats put in at some point? I can’t see any parting lines. Is there any way to tell if the seat is hardened?

One last thing. The exhaust valves sit low on the seat. The seat to valve contact point is right at the bottom of the valves. Factory size on these was 1.54” valves. Should I get some 1.54” or 1.60” exhaust valves for this?

[mag2555]

Go with a 1.60" valve and keep in mind that even though the guide looks like a bad restriction it's not , it's the width and arc of the short turn that is to a far greater degree.
Also keep in mind when reworking the port that since the valve is over on one side of the cylinder the bulk of Exh that the Exh valve gathers up come from the center of the cylinder, this makes alarge part of the Exh flow that enters the bowl lean over the Intake valve side of the guide and want to dive into and around the cylinder wall side of the guide.

The overall runner lenght of these ports is very short and as such the crown / high point of the short turn is near right at the flange, so hear is where the roof needs to be raised.

Two easy to make templates make reworking things way easier, faster and far more accurate when you do not have a flow bench to guide you!

[Carnut1]

Travis has a new best friend with a flowbench so he will be able to see progress. Watch exhaust bowl on intake side expecially going to a bigger valve. For the power these will make I would keep stock size unless they are sunk too bad. A sonic would be a good investment if you are having a good time with this. Give the bowl a nice radius from seat to roof on intake side of bowl but do not hog it out. Cylinder wall side you have more iron and can take more out but that also depends on the lift and how much power you are shooting for. Under that massive lump is water but I would grind it till my hands hurt.

[Carnut1]

20170629_211650.jpg

The 1.54" valve from a 351w is a nice upgrade and they do look beat for a 1.46". Check to see if the insert can handle the larger valve. I included a pic of Bill C' s cnc 289 exhaust port to give an idea of the shape you should be shooting for. These are not the same castings so water may be in different spots. Bill has these down and knows where the water is and flow. Bill has guys making stupid power on cnc Ford castings.

[mag2555]

Just to make you feel better these Exh ports with there stock 1.450" Exh valve flow a tad better in stock form then the iron 460 heads do with there 1.72" Exh valve in stock form!

That's less flow with a 18% bigger valve which makes for a stock Exh to Intake ratio of a beyond miserable 48%!

If you step up to a 1.60" Exh valve and blend things out in the right areas you should get close to 160 cfm to take place and if someone guides you who knows what there doing numbers in the low 170s can be had.

[travis]

These from the factory had 1.54” exhaust valves...not that they flow any better than a 1.45” in an E7TE from what I’ve read.

I’ve worked on some D3VE’s years ago...the exhaust ports on those was horrible for sure!

[JoePorting]

If the goal is max power, I'd keep the exhaust valve as small as possible so that you can make the intake valve as large as possible. Intake makes power, exhaust doesn't.

[EDC]

If the goal is max power, I'd keep the exhaust valve as small as possible so that you can make the intake valve as large as possible. Intake makes power, exhaust doesn't.

On the three bar GT40 heads I did up a long time ago for a stealth project, found the same concept applied to those castings. Cut down a 2.020" to 1.980" and a 1.600" to 1.550" and it worked like a charm.

[JoePorting]

If the goal is max power, I'd keep the exhaust valve as small as possible so that you can make the intake valve as large as possible. Intake makes power, exhaust doesn't.

On the three bar GT40 heads I did up a long time ago for a stealth project, found the same concept applied to those castings. Cut down a 2.020" to 1.980" and a 1.600" to 1.550" and it worked like a charm.

I would have increased the 2.02" to around 2.10", or within .040" to the exhaust valve, which ever would allow for a larger intake valve.

[EDC]

If the goal is max power, I'd keep the exhaust valve as small as possible so that you can make the intake valve as large as possible. Intake makes power, exhaust doesn't.

On the three bar GT40 heads I did up a long time ago for a stealth project, found the same concept applied to those castings. Cut down a 2.020" to 1.980" and a 1.600" to 1.550" and it worked like a charm.

I would have increased the 2.02" to around 2.10", or within .040" to the exhaust valve, which ever would allow for a larger intake valve.

You'd hit water at the short turn trying to get the throat/bowl right...

[travis]

Still whittling on the backside of the guide boss, but does it look like I'm going in the right direction?

[GARY C]

It would be nice if someone had some actual power numbers instead of just what flows better, I think it has been established over and over that exhaust flow numbers and bigger exhaust valves rarely equate to more power. You will find several race heads on the market that have a 1.55 exhaust with a 2.225 or larger intake valve which also blows a hole in the Int to Ex percentage theory...

[travis]

It would be nice if someone had some actual power numbers instead of just what flows better, I think it has been established over and over that exhaust flow numbers and bigger exhaust valves rarely equate to more power. You will find several race heads on the market that have a 1.55 exhaust with a 2.225 or larger intake valve which also blows a hole in the Int to Ex percentage theory...

I don't disagree with that at all...if you have a halfway decent exhaust port to start with. Fords are not known for having decent exhaust ports

I'm not doing much more to these. Hurts my hands too much messing with this iron junk

[GARY C]

It would be nice if someone had some actual power numbers instead of just what flows better, I think it has been established over and over that exhaust flow numbers and bigger exhaust valves rarely equate to more power. You will find several race heads on the market that have a 1.55 exhaust with a 2.225 or larger intake valve which also blows a hole in the Int to Ex percentage theory...

I don't disagree with that at all...if you have a halfway decent exhaust port to start with. Fords are not known for having decent exhaust ports

I'm not doing much more to these. Hurts my hands too much messing with this iron junk

We need to see if they are quiet and steady more so than how much they flow... BTW you need a Foredom Grinder... Just saying.

[mag2555]

Increasing the bowl radius ( cutting out the taper as the bowl drops down to the guide) on the back side of the valve bowl down near the guide is a sure fire way to drop off low lift flow and add pulses into the flow at certain lifts, that on a flow bench can be heard and seen in the test pressure bouncing up and down.

Have you had this head flow tested yet in stock form?