Just wondering if a first-timer can really screw up a set of heads so that they preform worse than from the factory, most importantly if they grinded the floor mostly instead of focusing in the proper places? Thanks, btw this can be moved if it isn't for Advanced Tech, just wanting to get the experts opinions here.. Thanks

 

i think im going to be safe in saying yes... nothing exceedes like excess, and i beleive it is rather easy to over do it. actually i watched a good friend of mine lost 20-30 cfm across the board with portnig a set of brand new fast burn heads. if you keep it mild you should be fine, if you concentrate in just removing all the casting irregularities i dont think you can go wrong. and everything i have heard has told me not to worry about the floor at all most of you flow is at the top of the port. also ive heard the the most important parts are .5 in above and below the valve. also a good 3 angle valve job will net some good results. anyone else have any ideas on this?

*Eric*

 

the biggest mistake is not keeping all the ports the same. Another big one is grinding too much and breaking through to a water jacket. That's a PITA to fix...

 

yeah, i had that happen to my first set! but now i know how far i can go..lol!!

 

First-time DIY porting is a lot like first-time DIY plastic surgery; you have to know where to cut to get good results. Good plastic cutters and good head porters need some basic training and some amount of practice before their results are really worthwhile.

I've always wondered where plastic surgeons practice? Porcine (pig) skin and tissue is a lot like human tissue. I think some practice is done on pigs (after, not before the slaughterhouse).

And why do doctors call what they do "practice"? Don't they ever get fully qualified?

Just teasing this board's resident sawbones.

 

I've always wondered that myself....

Crazy95Z-
You can check out this write-up I did way back in 2000 or so. It's still somewhat effective for the first timer. Click on "head porting" on the left. http://members.***.net/gmarengo/

Mike

 

You can definitely do a bad hack job and kill velocity in the valves. Flow is important as is velocity. A lot of times you'll see someone gasket match the intake ports, and hog the runner out all the way to the bowl. On my first set of heads I did a lot of research before beginning and started out very slowly. I did the gasket matching with a dremel tool before I started getting into the runners with a die grinder and a good set of bits. All I did was smooth the floor of the runners without knocking them down any. After that I flattened the roof and blended that into the bowl area while streamlining the valve guide.

I did some minor reshaping to the combustion chamber to unshroud the intake valve and really smoothed the surface.

I didn't spend much time on the exhaust port. I streamlined the valveguide, opened up the bowl area a little and enlarged the runner a little.

BTW I wouldn't consider myself an expert on this, but I do feel pretty good about the first set of heads I did. I wish I had gotten them flow tested, but was in a time crunch to get them finished and on the car.

 

make sure you get the short side of the intake runner smooth.... I did a "so-so" job on mine and the heads got pretty turbulent at .600 lift. live and learn.

 

So do you guys still think, even after your mistakes, that is was worth it? I mean, how much track/dyno improvement did you see even with your mistakes? Much better than the stock castings?

 

here is another common mistake for first timers. when doing the bowl area you need to make the aproach to the seat contoured you dont want the bowl to be a straight drop from the seat. I did this to my first set back in 1999 or so.. It ran like crap after the portwork and I did do some reading beforehand but I didn't upgrade the came or anything right back on the stock shortblock. now with 5yrs of exp. I do a lot better. and yes it is worth it just do as much reaserarch as possible before you start. I have a set I did for my car on here fs that flow 257 from L98's it is free hp so it's worth learning. it was good for a 7.6 1/8th at 91mph no stall and a slipping trany. prev best was a 9.5 with less cam and stock heads. the stock flow was 210