If torque is all you are after, stop where you are.

Only thing I might still do would be making the exhaust side valve guide area look like the intake pic.

Looks good.

Well, I may have overstated my thirst for torque and understated that for horsepower. Almost being an engineer (2 years at engineering school but finished up in math and physics) I understand the relationship between torque, RPM, and horsepower. And, I also have the mindset that makes me want to tweak everything that last little bit to get all I can get.

But, let me put it another way. The Comp Cams CamQuest software not only gives peak HP and torque, which is what everyone seems to focus on, but also the average for both and which I think is very important. Stock D8OE heads [Edit: With Performer intake & carb, long-tube headers, and XE250H cam) should give 236/390 peak HP/ft-lbs, and average 55 & 102. But, do nothing but bolt on a pair of seriously-ported D8OE's and you get 309/398 peak and 84/132 avg. While the peak torque only improves 2% the average torque improves 30%, which is something you'll really notice.

So, I'd like to rethink and restate my goal - strong average torque. And, given the relationship between torque, RPM, and horsepower, the result will be higher peak and average horsepower.

As for the exhaust guides, I'll work on them. Thanks!

Ported the other head today and in doing so I got brave and took more out of the right wall of the intake port. For reference, the gasket opening measures 1.075" wide x 1.925" tall, but the intake port in the head necks down to .85". Yesterday I took the head out to .95" wide, but stopped at that point for fear of grinding into the bolt hole. Today I took this head out to 1.0" and, since I got by with it, went back and did the same on the other head.

While that may not seem like much, taking .15" off for a distance of almost 2 inches times 8 ports is removing a lot of metal. (More than one way to get better gas mileage - weight reduction is under-rated. ;)) But, that really fixed the problem with the "throat" in the intake runner. Whereas before the runner necked down and then opened up again, now it just gradually reduces in size until it gets to the pocket.

Once I finished with the carbide burr, which leaves a fairly smooth finish, I used a stone in the Dreml to give the texture that is advantageous for an intake port. Here's the finished product:

https://www.ford-trucks.com/forums/p...ictureid=81672

And, I took more pains with the exhaust valve guides, as Stang suggested:

https://www.ford-trucks.com/forums/p...ictureid=81674

So, I think I'm "there" with that part and will start polishing the combustion chambers tomorrow.

Still haven't heard from the guy with the flow bench. He's always been a "free spirit" and does things his way. His shop is very well supplied with every tool imaginable, but he doesn't have a phone. Called my machinist who had heard where he was earlier today, so maybe he can track him down. But, we have until Monday as I want to do it Tuesday, so don't panic yet.

Opening the throat should help higher rpm flow(horsepower).

Just to the left of the valve guide area in the upper photo, it looks like an edge that could be rounded more....

I would not go any wider on the throat as once you go through the port wall.... Hard to repair if at all.

Stang - I'll check out both heads for things like that sharp edge and round them. Thanks. And, I fully agree on the throat. Don't really expect to wind this thing up so don't need a lot of flow, but didn't want obvious obstructions like it had.

As an update on the flow bench work, I haven't heard from the guy in my hometown. But, I found this craigslist post: High Performance Head porting and Flowbench Services. I contacted him via email and he said he's out of town at a contest but will be back Sunday. Hopefully I can go there on Monday and test the heads. I think all I need is one cylinder on one of the ported heads and one on an un-ported head. That'll give me a before and after view, and also tell me whether I've achieved what I want. Or, said another way, I'll plug the flow #'s he gives me into the dyno software and see if I like the results. I don't see a need to test all cylinders on both heads since I know there will be differences. If this were a race engine I'd go all out, but for my truck I don't think an all-out effort is needed.

On another front I ordered a burette last evening and should have it in a week or so. Maybe late next week I can cc the heads and, hopefully, finish the head-work portion of the build. I'm cleaning the shop now since I don't feel inspired to polish the combustion chambers on the heads until I know I'm going to run them.

That'll put me in a position to hang the block on the stand, run a tap through all the tapped holes, a brush through all the oil passages, and then blow it out. Then I can put the mains in, lay the crank in, put a piston/rod assembly in, and check the deck height. And, I'll cc the dish in the pistons and measure the head gaskets. With all that I can then calc the compression ratio. But, I expect it to come in about 8.5:1 - the same as stock.

Anyway, that's today's update.

I have seen people port through a head bolt hole, then drill it slightly bigger, and press a sleeve in the head bolt hole. then you end up with a hump in the port, but sometimes better than trashing a head. Also seen JB weld....

Once I feel the need to rebuild my 351w, I am leaning toward being lazy and getting some nice aluminum heads. But if I get cheap, then I am going to do similar to yours.

Also, that "restriction" at the throat is not a restriction until higher rpms. Making the port larger also has the drawback of reducing port velocity, which reduces atomization. Slow velocity can cause the fuel to drop out and/or form larger droplets that are harder to ignite. (lower efficiency/power/mileage)

I would also get some aftermarket pistons and go for about 9.2-9.5:1 compression.

Sorry, I was rambling....

BTW, which intake is going on this?

No, you were spot on.
I've used Devcon steel filled epoxy to raise many an intake port floor.
Never had the patience to weld up exhaust ports, but have fixed some holes where I "found water". :o :-banghead

Aluminum is fun to port in comparison to iron.

When you guys talk orientation, where is the floor, bowl, and the other terms you use? Can you use Gary's cross-section pic and point out the different terms for me? Thanks!!!

Well, I'm no good with MS paint or whatever others are using to mark up these photo's.
I can tell you the roof is the side of the port that the valve guide and stem come out of.
The floor is the side of the port that the valve seat is on **before** the short side bend. (if you were to draw a straight line coming down the port)
The bowl is the port directly adjacent to the back side of the valve. Typically only beyond the valve guide boss.

Here's an image from Wikipedia
https://upload.wikimedia.org/wikiped...Port_parts.GIF

Cylinder head porting - Wikipedia, the free encyclopedia

Here's a simple tutorial: http://65corvette.nonethewiser.net/t...al/diyport.pdf

The problem I have with the aluminum heads is they all have large valves and runners since they are designed for high RPM power. I'm looking for low RPM power/torque, and my understanding is that comes from smaller valves and passages.

As for the "restriction", my worry was that it sped the mix up and then it slowed down on the other side of it, and the latter would cause fuel to drop out of the mix. So, I brought the runner's width out to match that of the intake manifold, which is a Performer - not Performer RPM or Air Gap as they are intended for use starting at higher RPM than the Performer. Anyway, my thinking was that best bet would be to have a consistent runner volume, and therefore speed, and then decrease the volume gradually as the head does as it nears the valve.

On the compression ratio, I would like a bit more but I already have new pistons from the machinist. But, if these heads don't pan out I'll go for some with smaller combustion chambers and that'll raise the CR.

But, I'm the novice here as this is the 2nd set of heads I've ever ported. I've read volumes on the subject, but you guys have the experience. PLEASE tell me what you think, even if I don't like it.

Now that is just friggin awesome! I saved both the Wiki link, and the .pdf

Thanks bunches!

Gary, Torque comes from a lot of things. Rod length to stroke ratio, compression, cam timing and overlap,,, not just port and valve sizes.
Aluminum can support more compression because it is a more effective conductor of heat and that suppresses detonation.
Aluminum heads don't ALL have huge ports. Many are cast with small ports so the engine builder can port them as they please.

See Bernoulli and Venturi.
Bernoulli's principle - Wikipedia, the free encyclopedia
Venturi effect - Wikipedia, the free encyclopedia
Constriction necessarily causes both an increase in velocity and a drop in pressure. The consequence is also a loss of kinetic energy.

I think they look great for what you are trying to accomplish.
As you already understand all the pieces have to work together.
Huge ports and a mild cam with little overlap and a lower intended redline will just make your truck harder to drive.

I'm a dilettante here, and don't have too much experience with automotive heads. (maybe half a dozen pairs)
I've done plenty of motorcycles though. (both 2 & 4 stroke)
Some ports I've seen defy all "logic" but they just work, and the dyno sheets prove it! It is both an art and a science.
The thing is, with better metallurgy, casting techniques, 5 axis CNC, etc.. there's far smaller gains to be made in modern vehicles.

Just be sure you have good quench with those new pistons. You may be surprised how much compression and advance you can use.
If they mock up too deep in the hole you are far better off to deck the block than buy another set of heads with smaller chambers because you will make things worse and always have problems.

IMHO

Jim - I had plenty of physics getting my degree, and remember those guys quite well - one a Swiss and one an Italian IIRC. The statement about kinetic energy being lost is a better way of saying what I meant.

And, I agree there are lots of ways to increase torque beyond flow efficiency, but I'm doing a low-buck build and changing the rotating assembly is expensive from what I've seen - as are Al heads. But, I wasn't aware there are some small valve and port aluminum heads available, so I sit corrected.

On the CNC mill, I keep drooling over my nephew's CNC'd mini-mill. The same electronics would run my knee-mill and I could make all sorts of cool things. But, even then I couldn't do all that needs to be done on heads as my mill won't nod or tilt under power.

As for decking the block, I hadn't considered that. I'll get it mocked up soon and find out where I stand on piston height. Got the old head gasket measured today, so just need a few more measurements to know what I've got.

With all the help I've gotten I have a feeling this is going to turn out pretty well. :-jammin

Gary,
None of it was meant as criticism.
Like I said all the parts have to work together.
I was just trying to point out that cam + timing have effect and compression DEFINITELY has effect on torque output.

The newer 5 axis CNC machines are awesome. How far they can reach into ports and the repeatability is amazing.

CENTROID CNC Video CNC Cylinder Head Porting Video 5 axis CNC milling machine - YouTube

5Axis Machining cnc [www.disn.co.jp] 5Achs DMG/HyperMILL - YouTube

What criticism? I didn't take anything you said as criticism, and I'm sorry if my response implied it. Ahhh, the part about the degree? But, that was literally 42 years ago! But, I meant what I said - "I remember those guys quite well". Not what they discovered exactly, but the guys themselves. Sorry if my response sounded ..... arrogant. Give me a break, please. I'm a technical type, not one of those people who can use the English language.

Wow, those are cool videos! Amazing that they can twist and turn a head that much and that quickly to get the desired result. Makes my hopes to put 3-axis on my mill seem very tame.

Anyway, thanks for all your help. I really don't know what I'm doing and sure appreciate the help from those of you that do.