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I'll let the pictures explain themself. Ported partially a 799 head, took it to a well known machine shop and said I went too far on the short turn radius on the intake port. Sorry my port looks so ugly, how are you guys polishing them? My valve seat is obviously trashed too. Woops. Live and learn!
Yes, live and learn. Next time, send them to a shop that specializes in porting and uses CNC machines. Hand porting is so hard to get right and will take you 60-80 hours. All these heads need is a simple bowl port to make them better, unless your going max effort.
I clean up my stuff with cartridge rolls and cross buff wheels.
That's not the worst I have seen. We could salvage that I am sure I would have to get the heads here and see what you have to have fixed.
We just lowered the price on our CNC only job to $499.99 this includes a 5 axis cnc port job hat was developed bu Livernois Motorsports done in house by hand the first time then perfected and loaded into our CNC machine for the final product. We also have options such as competition or street valve jobs if you need a seat replaced we can do that also along with guides.
Give me a call text or e-mail for any questions you may have
Sincerely
Scott
Office 313-561-5500 ext 122
Cell 313-213-0273
E-mail smitchell@livernoismotorsports.com
It's admirable that you want to learn to hand port and touch up cylinder heads. That's definitely a hardcore hands on skill to learn.
An experienced shop can possibly save that by welding up etc and then CNCing. I'm ot sure if it would be lead expensive to just replace the head vs repair and CNC. I had an ported LS3 head more badly damaged that could be saved by welding and CNCing.
Going forward to practice hand porting there are a lot of damaged LS heads that would be good practice to work over. Likewise, 806, 853 & 241's are dirt cheap - a set for $50 to have 8 ports and chambers to practice on is reasonable. You might want to befriend a local shop with a flow bench. Would be a good way to measure progress and if the shop is skilled maybe learn too.
When hand porting for the first time, you want to clean up and taper in the port to improve flow. The old method would be to place an intake gasket on the head and mark with a pen. Then instead of trying to hog out the entire runner to the width of the marker line, a wise move would be to take out the edge to marker line and taper it in for about an inch until it blends in evenly with the runner. Then clean up any sharp bends and remove some of the metal around the valve guide boss. Leave the throats alone. You can polish the bowls but don't attempt to blend them.
Thereafter, taper remove some metal from the roof and sides of the exhaust port, but not from the floor. Polish all of your work. This method will get you about halfway to max air flow without ruining the head. If the above takes you more than 6-8 hours, you are either removing too much metal, are really slow, or are working on an iron head. As time passes you will build up confidence, and later will be able to open up the runners, cut the throats, and blend the bowls. Another tip is to add cut back valves with undercut stems. That can be worth about 20 CFMs without a lot of port work. Good luck.
The thread above has pics of the first heads I ever did - a pair of 706s. I was very conservative with what I removed and where I removed it from, especially in the bowls which exhibited some nasty core shift. Using long double-cut carbide bits it left a surface no rougher than any CNC'd head - so no feel good polishing was done on these junkyard heads. Buy a cheap set of snap gauges to ensure consistency between ports, and use a strong LED light to guide you with cascade and shadow. It was a long process, that cannot be rushed.
01-21-2019, 03:06 PM
How bad did I screw up this head? 
