port and polish stock heads

[Shaggy67RS]

From everything I've seen, there's a real science to porting. It's a lot more complicated than just grabbing a grinder and shaving down metal. How much you remove from specific places, and exactly how you shape things makes a really big difference. The guys that are good at it have a lot of time and experience invested in learning exactly what places in the head can be ported to improve HP.

You might get lucky just taking a guess at it, but then again, you might not.

[94zgreenmachine]

For anyone that doesnt know what the biggest difference is: Lloyd hand ports his heads and AI uses machines.

both get excellent results, however I would have to say that AI is going to have the more consistent results for obvious reasons.

Very true. I have had an LE set up and I have since switched to Advanced Induction. There certainly is a difference in the quality of the work done by Advanced Induction. My heads looked excellent and at least I know my ports will be spot on and be consistent. To port heads by hand and be consistent would have to take 40+ hrs.
My LE set up was fast, probably high 11's but I am hoping that with the cnc work that an extra 20 hp will be there because of the consistency of the ports.

[Adam]

For anyone that doesnt know what the biggest difference is: Lloyd hand ports his heads and AI uses machines.

both get excellent results, however I would have to say that AI is going to have the more consistent results for obvious reasons.

You forgot to mention that AI heads are easily double the price. And you can still achieve great numbers with LE heads. Yes LE hand ports but when you do several hundreds of heads, your pretty good at it. A set of AI heads would definitely be consistent with a machine port, but you will run great numbers with either company. I'm not going to say one is better than the other. I would just like to say you should buy what's in your budget for what you want to achieve.

[94zgreenmachine]

You forgot to mention that AI heads are easily double the price. .

For a comparable le3 and AI 200cc there is a difference of only a few bills and that is head and cam together. For the extra 20 hp that may be left between consistency and hand porting, it really isn't that much more $ between the two.
I honestly can't say how well my AI stuff performs, yet. The car is still in a million pieces, but hopefully in the next 3 weeks I can definatly post some times and see......

[Shaggy67RS]

Might be a long shot, but do either LE or AI ever stamp anything on their heads that identify they ported them. IOW, if I've got an unknown set of ported heads, any chance of telling where they came from? Anything to look for?

Like I said, probably a long shot.

[94zgreenmachine]

Might be a long shot, but do either LE or AI ever stamp anything on their heads that identify they ported them. IOW, if I've got an unknown set of ported heads, any chance of telling where they came from? Anything to look for?

Like I said, probably a long shot.

Both will stamp your heads with your initials. The difference is in the cam. LE has it written on his cams if it is a le2 le3 , etc.
The real way to tell is in the machine work and the ports. A cnc will leave a definate pattern where as a hand port will look like it has been polished all over. My LE heads had somewhat of a mediocre finish on the deck surface. Almost like they were on a grinder compared to a mill finsh.
I have had both.
It would be hard to tell the difference between hand porters or cnc head porters unless, you knew what "tricks" they have. But you can definately tell between cnc and hand.

[Shaggy67RS]

Thanks, good info. I've seen some numbers on the top of the heads (under the valve covers), but I figure that's probably just casting numbers from GM.

[Fixxer99TA]

If you come across the numbers again, post up pics..

We can tell you

[James Montigny]

There's a lot more to porting than simply removing material.
It really is a complex process to determine what should be removed and what should not.
I prefer to leave it to the pros or buy an aftermarket casting.

Here's an article from Standard Abrasives that may help give you an idea of what is involved.
http://www.sa-motorsports.com/diyport.aspx
I remember reading it years ago when finding a good head porter with documented results on LT1s wasn't so easy.

Summary from article:
- Intake port entry enlargement, surface finishing and port matching.
- Smooth the intake short side radii, valve guides and valve pockets.
- Smooth the exhaust short side radii, valve guides and bowls.
- Exhaust port and bowl polishing.
- Combustion chamber polishing.
- Intake manifold port matching.

[97T/A]

Lloyd Elliott is a great guy. Give him a call and he will fill you in on anything you want to know.