Hand porting heads
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On The Tree
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From: Philadelphia, Pa
Hand porting heads I've decided to hand port my 799 heads before I reinstall them. I have the porting kit made by Eastwood and a set of carbide removal tips. Has anyone hand ported heads before? Any tips before I get this started?
I've had VERY good results with my home ported heads. With not only LS heads but with Ford 750 carb 347 about 425hp and LT1 heads. FYI with stock bottom end, my ported heads, 503cc cam ported stock int and 58mm TB and shorties I put down 390rhp/366tq on an LT1!! With 6spd and 4.11s it was such a nice balance of power, hook and fun.
Point is plan on time and don't do too much, focus on visualizing flow. I do about no less than 8 hrs per head. I got 241s that will make some power.
Read up and try it on stock heads that are cheap.
Point is plan on time and don't do too much, focus on visualizing flow. I do about no less than 8 hrs per head. I got 241s that will make some power.
Read up and try it on stock heads that are cheap.
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On The Tree
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From: Philadelphia, Pa
I guess my main question is this:
How much can you take the swirl down? I've seen people online who've taken them all the way down. But I have also seen people post not to take them down.
How much can you take the swirl down? I've seen people online who've taken them all the way down. But I have also seen people post not to take them down.
I have hand ported every set of cylinder heads I have done. Many people will tell you that cylinder heads need to be CNC machined or you need to go with XYZ shop to get results. I have quantified my results on live running motors along with the flowbench. Most CNC port jobs will fall short of their claims and most aftermarket heads have no real advantage over an ls6 head that is properly ported unless your pushing for huge port volumes. A few tips for a beginner would be to straighten out the straight wall, don't really touch the swirl ramp and open up the bowl or the throat aka the 1" below the valve to 1.78 to 1.8", and get a valve job by someone reputable. Your porting kit will more than likely fall short of being able to do this job as most kits are garbage. Get a few 6" shank carbide burs for aluminum and you should be set.
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On The Tree
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From: Philadelphia, Pa
I'm not so sure I want to follow the guy on YouTube all that much. He punched holes in his heads in a couple of spots. I'm going to be a bit more conservative than that. I'll be posting some pictures as I go. Giddy up!
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Joined: Jul 2010
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From: Huntsville, AL
I "ported" my 799's and got good hp numbers, no flow bench numbers though. I focused more on smoothing transitions and blending the bowls than really changing the shape much. I left the swirl ramp and only knocked down the rocker stud bolt some since I didn't want the hole. You can mess them up pretty quick if you are too aggressive.
I wouldn't risk a set of 799s to my first experiment in porting.
Far as hand VS. CNC, CNC porting generally starts as hand porting and then is measured for the machine to duplicate over and over. A LOT easier for a machine to be consistent over and over and a lot of hand time can be put into that first master port.
For serious reshaping on a modern port injection motor I will always choose CNC, on a TBI or carbed motor is a port is better or worse than the rest the fuel and air are already mixed and it gets roughly the right mix, on a port injected motor where you are only measuring the average AFR of a bank a good flowing port can make for a lean cylinder while the next one could be lower flowing and rich and the wideband shows a good average.
That is not to say hand porting is no good, it is just to say that IMO port to port consistency is more important on modern engines than older ones and ye I know intakes introduce some cylinder to cylinder variation too.
Being a fellow gearhead I get wanting to port a set yourself but I would use a set of 5.3l heads or 241s and save the 799s at least till you know you made a net gain with the cheap heads or till you want to step up to professional work.
Far as hand VS. CNC, CNC porting generally starts as hand porting and then is measured for the machine to duplicate over and over. A LOT easier for a machine to be consistent over and over and a lot of hand time can be put into that first master port.
For serious reshaping on a modern port injection motor I will always choose CNC, on a TBI or carbed motor is a port is better or worse than the rest the fuel and air are already mixed and it gets roughly the right mix, on a port injected motor where you are only measuring the average AFR of a bank a good flowing port can make for a lean cylinder while the next one could be lower flowing and rich and the wideband shows a good average.
That is not to say hand porting is no good, it is just to say that IMO port to port consistency is more important on modern engines than older ones and ye I know intakes introduce some cylinder to cylinder variation too.
Being a fellow gearhead I get wanting to port a set yourself but I would use a set of 5.3l heads or 241s and save the 799s at least till you know you made a net gain with the cheap heads or till you want to step up to professional work.
thats normal. youll get that hole when you take down the bump in the intake port. no need to worry. your rocker arm bolt wil fill it up just make sure to put sealer on those bolts.
also like a few mentioned dont smooth(like mirror finish) the intake side as much. however smooth the exhaust chambers though but be cautious of the coolant hump passageway. get a few 6" shanks and a nice carbide kit for aluminum. also get them in 1/2" size, no smaller!
On The Tree
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I have photos videos and some tech in diy porting in this tread.. If you want I have some 799 that are ported i can swap your crew plus 550..
https://ls1tech.com/forums/generatio...d-porting.html
https://ls1tech.com/forums/generatio...d-porting.html
Staging Lane
Joined: Jan 2013
Posts: 66
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From: Black Hills
I have photos videos and some tech in diy porting in this tread.. If you want I have some 799 that are ported i can swap your crew plus 550..
https://ls1tech.com/forums/generatio...d-porting.html
https://ls1tech.com/forums/generatio...d-porting.html
Last edited by ur-n-8; Jan 24, 2014 at 08:55 PM.
It has been discussed several times.
Look in these 2 threads for pictures, tips and, general advice. You don't want to polish the intake side smooth as you need some turbulence. In the combustion chamber polishing will help prevent detonation and reduce carbon build up. Same with the exhaust ports, it will reduce the carbon soot build up.
https://ls1tech.com/forums/generatio...-can-help.html
https://ls1tech.com/forums/generatio...799-heads.html
Look in these 2 threads for pictures, tips and, general advice. You don't want to polish the intake side smooth as you need some turbulence. In the combustion chamber polishing will help prevent detonation and reduce carbon build up. Same with the exhaust ports, it will reduce the carbon soot build up.
https://ls1tech.com/forums/generatio...-can-help.html
https://ls1tech.com/forums/generatio...799-heads.html
On The Tree
Joined: May 2004
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On The Tree
Joined: May 2004
Posts: 122
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Staging Lane
Joined: Jan 2013
Posts: 66
Likes: 7
From: Black Hills
Yeah I guess someone should define "polish". It looks to me that the ports are finished to 80 grit or finer. While they are not shinny they are very smooth. I think they look very good, by "look" I mean they are very uniform and consistent. Not just shined up for someone to look at.
