LT1-LT4 Modifications 1993-97 Gen II Small Block V8

DIY head porting??

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Old Apr 25, 2006 | 01:36 PM
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Default DIY head porting??

has anyone tried porting their own heads??

if so let me know I amthinking about doing it for the first time.


Ed
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Old Apr 25, 2006 | 01:43 PM
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Uhh No !!! Bad Idea, unless you really know what your doing. There is more to head porting than just hogging out the port or think your just gasket matching. I would recomennd a BIG negative on this idea.
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Old Apr 25, 2006 | 01:58 PM
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Originally Posted by edlt1
has anyone tried porting their own heads??

if so let me know I amthinking about doing it for the first time.


Ed

I get a lot of work from people who try and port there own heads. You'll do more harm then good, there will be some guys on this forun that say otherwise, but I have seen many heads to far gone to fix.
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Old Apr 25, 2006 | 02:17 PM
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I tried on a set of LT1 heads.

Did 3 cylinders and left one stock (just one head). Took them to get flowed. Stock was something like 205 cfm on the intake... my "ported" intakes flowed from 215 to 230. OK, called for more porting.

So I ported all 8. New valves, valve job, the whole bit. Took them and got all 8 cylinders flowed. Lowest cylinder intake flow was 195, highest was 230. Port volume was huge. At this point I said screw it, cut my losses, and bought a set of professionally ported heads.

After talking with the flow bench guy, I did learn what to look for in a bad port job. But I didn't want to pay him any more money for flowbench time (it ain't free, ya know). I chalk it up to a learning experience. I spent about $400 for that 'lesson' in head porting.

If you have free access to a flowbench, I'd definitely go for it. Without one, you're shooting in the dark (as I was).
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Old Apr 25, 2006 | 03:36 PM
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my friend did it to my heads and the car dynoed 390/390 through a street twin and a denny d-shaft and a 9 inch so I guess it was an alright job done. Well know when i buy my trick flows and have them ported by lloyd to see how much i gain
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Old Apr 25, 2006 | 03:54 PM
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I just started a set of mine. They're acually coming out really good. I did tons of research tho and practiced on a set of junk heads before starting.

here are some pics:



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Old Apr 25, 2006 | 04:07 PM
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Mine looked good too.
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Old Apr 25, 2006 | 04:20 PM
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How much thinner where you planning on making the common wall ? And are you going to try and straighten it back up ? Make sure to order some AB epoxy !!
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Old Apr 25, 2006 | 04:26 PM
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Originally Posted by MrBill97396
How much thinner where you planning on making the common wall ? And are you going to try and straighten it back up ? Make sure to order some AB epoxy !!
I've smoothed out the casting on that wall, haven't grinded much off.
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Old Apr 25, 2006 | 04:28 PM
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I know you wnat to make intakes kinda rough for fuel atomization, and combustion chambers and exhaust real smooth
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Old Apr 25, 2006 | 04:52 PM
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Originally Posted by MrBill97396
Uhh No !!! Bad Idea, unless you really know what your doing. There is more to head porting than just hogging out the port or think your just gasket matching. I would recomennd a BIG negative on this idea.
I have ported my own heads, but I havent ported LT1 heads though, If you do decide to port them out, I recommend practicing first, on some iron heads, then if you still want to do it buy a standard abrasives basic kit from summit, that is just an abrasives like sanding barrel cartriges and some buffing wheels, that will smooth out the air flow without the big risk of trashing your heads. DO NOT USE CARBIDE BURRS unless you have experience with them.
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Old Apr 25, 2006 | 04:55 PM
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man luckyou03 you did a really good job, I salute you
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Old Apr 25, 2006 | 04:58 PM
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You dont want them to smooth, then you start messing with the fuel puddling. that is why you use a fine grit cartridge roll. If you are planning on moving any material out you will need a good supply of cartridge rolls, and dont take any off the floor of the port. You could mess up the short turna and then you may as well toss them.
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Old Apr 25, 2006 | 07:54 PM
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Fuel puddling is not much of a problem on an EFI engine.

I ported my last 2 sets of heads - bowl blending, port bias work, guide shaping and port matching) - one was a set of GMPP Fastburn heads (more of a cleanup and port match) and the other was a set of new Edelbrock E-TEC 200 heads. They are in my Vortech-blown 383 now and running great.

I highly recommend David Vizard's book on Modifying the Chevy Smallblock Heads. Lots of pix and examples. Good through LT4 - the LSx heads are too different.

Take your time and use sanding rolls, not aggressive carbide cutters. You can ruin a head in 30 seconds with a carbide too if you don't know what you are doing. With sanding rolls you need to work at screwing up!

Jim
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Old Apr 25, 2006 | 08:41 PM
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i would also recommend David Vizard's book.
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Old Apr 26, 2006 | 10:40 AM
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Polish the intake port and yes you will have puddling
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Old Apr 26, 2006 | 04:25 PM
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I agree - no intake port polishing.

Jim
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Old Apr 26, 2006 | 04:40 PM
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Yea its better to not polish the intake manifold or the intake runners on the heads, only polish the exhast port and the combustion chamber to limit carbon deposits which will hinder airflow.
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Old Apr 26, 2006 | 10:58 PM
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I ported my first set by just reading about how to do it and asking around. I did have a flowbench to help me along though.

I went from 198 cfm stock to 237 at peak, with gains throughout midrange. That was still with stock valves, stock valve job, and untouched chambers.

I started messing with the chambers and blending and gained a little more (lost the exact numbers) but think it was about 10cfm.

With new valves, seats, and valve job, I dont see why it wouldnt be a 265cfm head.
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Old Apr 28, 2006 | 03:12 PM
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send your heads to loyd elliott, good price for an awesome result. heads are were all the power is made, do it right. good luck
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