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First time porting heads

20K views 62 replies 10 participants last post by  Camaro_Nut2001 
#1 ·
Well, I finally got the courage to start porting on my "062" Vortecs. I'm gonna fully port the exhausts and just barely clean up the intake ports along with gasket matching the intake and heads. I'm cutting the guides and seats, pulling the pressed in studs, tapping and installing shoulderless screw studs (gonna run self-aligning rockers so I don't have to cut the stud boss) and hope for the best. I think I am done with the carbide cutters on the first head and ready to do the final finish on the exhaust ports with cartridge rolls. Here are a few pictures. Please let me know if you think I'm headed in the right direction, completely off base or just plain ruined this head already. If I haven't ruined the head, please give me your advise on how i'm doing and any tips you have. Thanks, Ted.
http://www.hotrodders.com/forum/attachment.php?attachmentid=70253&stc=1&d=1357179111
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#2 ·
If you run the bit back and forth it will dig a hole and cut too deep on the outsides. Ends with a crown in the middle.

Sanding rolls will help smooth out the pinch points around the guiides. Might need to tear some off to get into the deepest part. Take your time and use smooth cuts agasit the direction of the bit. Dont use die grinder air power does not have good tq and will stall the bit and dig a hole when it does. Electric is much easier to control and produces a smoother finish. But dremel is not going to cut it you will need something with a hp rating and works at low and fast rpm.

Focus on just removing the ruff casted surface and leaving a smooth cut finish. Hanging the shape is not always the best idea. Usally the shape is made with a purpose in mind and is not easy to redesign with just cutting the port and not adding metal back in. This basic clean up will net you a real 3-5 percent increase.

Also changing the shape of the port can really mess up swirl porting and other flow devices that will actually hurt flow when the air is moving at hundreds of mph thru the port.
First off, thank you for the advice. Do you think I have hurt the flow on these exhaust ports? Like I said earlier, i'm not gonna do any cuttin on the Intake ports. I'm tryin to get these ports to look just like the ones in David Vizards book and it looks like he cut alot of the guide to make a smooth area completely around it and blended it into the exiting port. I have been using my die grinder cut down to 30psi. I'm gonna try to get to Lowes tomorrow and get a light dimmer to use with my electric die grinder as its way to fast if plugged into an outlet, 25,000 rpms if i'm not mistaken.
 
#6 ·
Thanks for the link. I have done a little reading on home flow benches and plan to do alot more. If I can, or better said, when I can, get this porting trick down pat I want to build a flow bench. Right now i'm just doing my best to not ruin the heads, lol. That Vizard feller has a heck of alot of talent when it comes to making power and he has a section in one of his books on building a flow bench. I think with more reading, and I read some and glanced some at the article you posted, I can build a pretty accurate one by combining information from both articles. Thanks again for the link!
 
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#8 ·
I was hoping you would chime in. After comparing pictures of mine and some of Vizards I don't think i'm ready for the cartridge rolls yet, lol. When you say streamline, do you mean taper the guide boss into the runner? Also, I read somewhere about not taking very much at all from the back side of the boss. I have looked at your profile pictures and didn't find any but do you have a picture or two of a completed exhaust port that you have done? Am I right by not messing with the intake bowl? I really do value your knowledge.
 
#9 ·
Well now, maybe I need to reconsider as everything I have read thus far says that on the Vortecs the intake side is close to impossible to improve and I figured with my very limited knowledge on porting I would be best to leave them be. What were you thinking needs to be done on the intake side?
 
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#10 ·
Now that sounds like just what I need!! I like the foot controller and really really like the flexable shaft idea. I never knew this tool even existed. Thank you for showing it to me! I do plan to get into porting heads as I have several friends that race, I build and tune their carbs, and its something I can do sitting down for the most part. I have several pairs of safety glasses and am a firm believer in them. When I get in from the garage tonight I'm gonna do some more reading on this tool and may just order me one. For everything that comes with it, $355.00 is kinda cheap. I paid almost $200.00 for my 8pc. carbide cutters.
 
#12 ·
that's actually about half way through, its also very important to blend the chamber in with the top cut of the valve job- which can be very tricky. I also didn't thin the guide any in that pic, typically I do thin it some but not as much as a lot of people do.

Just blending in the bowl cut and the top cut of the valve job on those heads will pick up 15 cfm, that area is very critical, and very tricky and time consuming as you do not want to nick the valve seat. smoothing out the short turn a little can help too, just don't get carried away. In general the areas closest to the valve seat are the most important. Also, enlarging the pushrod pinch a little and getting a nice and even contour on the roof will help with higher rpm power.
 
#15 ·
I got the guide bosses cut down and shaped as close as I could to the pictures in Vizards book. These pictures don't show the shape very good but they come to a point on the top of the guide and taper down. I'm kinda skittish on taking anymore out. Do ya'll think I should leave the intake ports alone or port them as well? Also, finished all the guides on this head. From the pictures it looks like I cut the spring seats but I just skimmed the top to knock the varnish/dirt off. Please let me know what ya'll think not only about the intake ports but all the stuff I have done thus far. I plan to either start pulling and taping the studs tomorrow or, if ya'll think I need to port the intakes or any other stuff, i'll do that. I do know i'm really enjoying this, lol. Here are the pictures
http://www.hotrodders.com/forum/attachment.php?attachmentid=70273&stc=1&d=1357282581
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http://www.hotrodders.com/forum/attachment.php?attachmentid=70277&stc=1&d=1357282581
 

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#16 ·
I'll get those numbers today. I did buy a pair of "062" that came off a running 2000 Chevy truck for $125.00 the other day but these i'm playin with are not them. By looking at what i've done on the exhaust in the pictures do you think I have improved them? By lookin at em and imagining(sp) in my mind the air flowing thru them I feel i've helped them but I would like your opinion. I will post the numbers a little later.
 
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#21 ·
A really good example is porting on F E heads. want to wake up a 390,port the exhaust uncork the exhaust system.Old dodge sb...port exhaust side.
want to make power with vortec heads,open the exhaust.
best after market heads have a high exhaust ratio.
dont want to use a split duration cam or thumper cam,port the exhaust
how many high powered cars have small exhaust?
 
#22 ·
porting the exhaust does help, so you'd be a fool not to do it if you're searching for max power, but it doesn't help as much as the intake.

You're making sweeping presumptions that really have no basis. And there's not a damn thing wrong with a split pattern cam or even a reverse split pattern cam- the cam should match the application and that means almost NEVER using the same lobes on the intake and exhaust.

If you have to pick a side to spend your time on spend it on the intake. And a very well ported set of Vortecs with a stock valve will pick up 30-40cfm on the intake at about .550" lift. Properly built that can mean about 60hp.

And I am NOT saying porting the exhaust won't help too, if you can they should both be done. It is just not as significant as the intake.
 
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#24 ·
Man, I sure am glad I got a phone call and didn't make it back out to the garage and you caught me before I started. Thanks FBird. I hadn't read, seen anywhere or heard anything about the studs on Vortecs and just assumed they were like any other sbc head. I was going to put screw studs in just in case I ever wanted to go with a bigger cam one day. I'm running the Summit K1103, 272/282-.442/.465 on a 112 lsa and running the stock rockers that came with these heads unless I change my mind and then i'll run these COMP Cams Magnum Steel Roller Tip Rocker Arms 1417-16 - SummitRacing.com.
 
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#26 ·
Thank you for the info on my combo, I actually picked this cam when I was gonna run self ported 305 heads, lol. Like I said at the first of this thread, this motor is goin in my '88 S10 with a th350 or th400, haven't decided yet, which will be used as my daily driver/sleeper truck.
 
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#28 ·
Thats exactly the gear i'm gonna run with an Eaton limited slip unit, i'm running one in my '69 Chevy truck and love it, already have the bars but was thinkin about fabbing a 4-link instead, don't know yet. I have my eyes on the tires I wanna run but haven't decided on them yet either completely. Do you think a 3000 stall will be ok for a long term daily driver? I wasn't plannin on turnin this motor over 5K rpms, and not alot of them.
 
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#34 · (Edited)
.. Your setup should HP peak around 5500-5700 RPMs, shift around 6000 or so...

.. 275-60R15 rear tires should fit under there...

.. Porting the intake ports is most important... you only have a max of 14.7 psi pushing air into the intake ports of a N/A engine... several hundred psi pushing it out the exhaust... Comp cams claims you can reduce exhaust valve lift by 2/3's with little effect on performance...

.. The exception, of course, would be engines with really horrible exhaust ports to start with... I've had to remove the air reactor boss from the ports of a '77 351W engine, it blocks about 80% of the port which was small to begin with... it wasn't even used on the marine engine I was building up... Ford should have sold Mercruiser engines without them... I don't think Mercruiser even realized the bosses were in there, since they didn't change the HP rating after the engines started coming through with the blocked ports... Mercruiser switched to Chevy engines the next year...
 
#35 ·
Ok, I finished one head and got the other one apart and measured my quench this afternoon after my doctors app. I came up with 0.0260 in the hole. I'm running a 4 valve relief flat top that i'm guessing is around +6 vol. and the Vortec heads at 64cc. Like I said earlier, i'm running the Summit K1103 cam-Advertised Duration 272/282, Lift .442/.465 on a 112lsa. The way I figured it, keep in mind i'm still learning on DCR and SCR, I need to run a .028 head gasket. Am I on the right track? If so what do ya'll think about this gasket- Chevrolet Performance Head Gaskets 14096405 - SummitRacing.com ? Is there a better gasket both quality and price? If i'm completely off base lol, what gasket do I need to run with my setup? I'm shootin for as close to 10.1cr as I can get. Thanks.
 
#40 ·
.. I get 10.24:1 static using 6cc pistons, .015 gasket, .026 deck, 4.030 bore, 3.48 stroke, 64cc heads, 8 cylinders(for cubic inches/L.) using Summit's compression ratio calculator. Lower C.R. if pistons have sizable champfer on top outer edge...

.. I would definitely use the thinner gasket for better quench effects/benefits and power... despite slightly higher compression ratio...

Compression Calculator - SummitRacing.com
 
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