Just wondering how many HAMB members have done any port work on cylinder head's. Something best left to the Pros. I just picked up a set of 461 camel back head's for the coupe,motor is stock. Just trying to get ideas on what to do. PINCHER
Also some good reading are the books written by David Vissar. His "How to build Horsepower" book is a good read. He has done alot of testing and experimenting for many years and thats what he bases his books on.
I ported my mopar 440 heads using their template kit, it was by far the biggest bang for the buck of anything I ever did to that motor. It is pretty simple porting, and I'm sure still give far less of a return than professional flow bench or CnC porting, but really costs nothing but about 10-12 hours of your time. The templates are a simple set of lexan 'cards' you cut out yourself, and they just ensure that you're removing the same amount of material in the same places in all the ports. I think you could apply this to any head, I would just smooth the bowls and pocket port the first port then make my own templates. Read the above mentioned books and they'll explain where gains are to be had, and where to leave well enough alone, and get started. Looking at a stock casting you can see where even by removing casting ridges and smoothing out obstructions can give some pretty substantial improvements. I did my stock heads and ran them on my near stock 440 for a season, knocking 4/10ths of my ets. For the next season I decided to go to larger valves. I took the heads to the machine shop to be plunge-cut and fitted with new guides etc and the machinist complimented me on a job well done. I then felt confident enough to polish and cc-match the combustion chambers, picking up another .24 on my et. To summarize, .4 improvement= total cost of 66 bucks, 15 for templates and 46 for grinder and carbides. .24 seconds faster, total cost, 240 bucks, 144 for valves etc and 80 for machine work. Total time spent= 13 hours on ports and 3.5 hours on chambers.
Every single pro porter including my childhood hero Joe Mondello started out porting their first set of heads. We tend to forget that. You may have the instincts of a gifted porter. If you dont try we will never know. Go for it. Think like an air molecule. Most of the ponies are hiding in the valve bowl under the seat. Very little is gained in the ports themselves on many heads. Big thing there is make sure nothing is hanging out in the airstream. Having ported many many heads I can also say tis a dirty job but someone has to do it. Don
Here's some good advice... Being that those #461 heads are getting pretty rare to begin with.. If I were to start all over again, I'd start on a scrap sbc head from a junkyard. A lopo cylnder head from a mid '70's chevy would be cool to start with. One other thing... Don't go hog wild or you'll break into a water jacket.
Good advise here. Thats one advantage that big block Mopar guys have is the porting templates from Direct Connection. I've heard more than a few pro porters scoff at the template jobs but 440dave is one of many that has picked up 3 or 4 tenths with this work. Knocking back that machined ridge in the bowl and blending the lower seat angle into the bowl will make a big difference.
Thank's everyone some good information here. I have some reading to do, and some junk head's to practice on in the shop.Yes it is a dirty job. Think i will give it a shot. PINCHER
I own a cylinder head porting business, sometimes there is more too it than people think. But it can be done by the everyday hotrodder with some attention to detail. First, you need to consider the application. Intended use, displacement, bore, stroke, cam selection, etc. If you are just looking to get a little better power from a good street engine it is plenty do-able to do at home. Just remember that the largest flow restriction in a SBC head is the valve seat and bowl area. 1 inch below and 1 inch above seat are most critical areas. Here are a few quick tips, A good valve job is crucial: Even just the right multi-angle valve job can help flow significantly, especially coupled with a back-cut on the intake valve (30 deg). Maintain maximum throught diameter: In short, don't grind bowl or area under the seat too wide. Stay away from all the bottom angles of the seat. Think of the seat as a venturi system. as the air/fuel approaches the seat, it accelerates through the seat and valve. Grinding right up to the 45 deg angle KILLS flow. Blend bowl: Just a simple blend of the bowl will help in a street motor. Be careful around the critical "short turn radius". Take your time, attention to detail, practice on a junk head as much as you need. P.S. I spent a week with Joe Mondello learning the trade from him one on one. I am honored to have had the oppritunity to spend so much time with him!
Another valuable thing you can do that doesn't cost anything is to look over a set of professional ported heads and if possible have a set of stockers along side to compare them to. A set of ID dividers is valuable when comparing the various parts of the ports. After that some careful grinding using what you have learned will get you in the door. Very noisey,dirty, time consuming but also rewarding if you can put your efforts on an engine and see what it produces. Like above you'll find a real cost effective activity that will only make you more curious about this voodoo art. Frank
Find a speed shop with a flow bench.................461's.291'2..186'..040's & 492's can flow with minimal port work. I had 2 sets flowed.............the speed shop got the untouched heads to outflow the ported heads......with mininal work.
I have seen alot of amateur ported heads and I would say 85% of them flow worse than stock heads. ( really don't want to sound negative, it is just an observation)
The reason so many so called "pro" ported heads flow so badly is that they have no idea what is going on in the cylinder head. Bigger is not always better when it comes to port size. Velocity is more important than volume in most cases. Removing only what is necessary is the key. If you increase the port volume by say 1% by removing material in the right area, and increase the flow by 10%, you have created more velocity. Thus increasing cylinder filling and increased your horsepower. Not ALL pro ported heads are bad, but it amazes me how many people consider themselves a "pro".
Leave the intake ports rough on a street driven engine. Obviously, you'll want to remove the casting flash and lumps, and as others have already mentioned, spend your time in the bowl and seat area as well as the 30* back cut on the valve. Polished combustion chambers help keep carbon build-up to a minimum. Polished exhaust ports are OK but are hardly noticed in street performance - this sort of thing is mostly for bragging when you go to sell your car to the uninitiated.
Well ,for my two cents,for me,I've found that this is only good for drag racing. As for street, the minute your start your car up and run it,,those pretty little ports get all sooted up and go back to bein' just what they were. All that pretty polishing was for NOTHING. Yes, you can remove flashing and imperfections that will give you some gain. But everything I've read says that the engineers know this and that rough casting adds to turbulence which INCREASES flow. That they didnt want smoothe. That rough flows better. so, I dont really fucking know what the fuck to think... and I'm gettin older...I've done and few and run em,and with all the fucking work I did,I didnt get much gain,maybe a little tiny bit...so,it didnt pay off for me..Mikey
I clean up the casting imperfections, smooth the valve-guide boss a bit, and give a nice radius to the short-turn. That's it... it works. How do you think I got my name???
i have done alot of porting even to the point of welding in the intake ports to move them around some. i can tell you if they are good 461 heads sell them to a colector use the money to buy a set of al. heads and be done with it.
Did mine myself, was just gonna do a simple gasket match and couldn't stop myself. Went all the way but kept it on the mild side. Gritty teeth & black boogers! I feel very "connected" to my engine now.
I used an OD grinder on a set of 1/2 long X 3/8-16 Allen head bolts that positions the Fel-pro intake gaskets on the heads perfecly. I first messured the I.D. mounting holes in the gaskets with inspection gage pins and then ground the OD to that size .050" from the bottom of the Allen head. Next: Mount the cylinder heads on a bare block and torque all the head bolts too?? maybe 45-50 foot lbs. Mark the area around the intake ports on the heads with some blue machinist ink and let it dry for a couple of minutes.. Then lay your intake gaskets in place. Then install and hand tighten the Allen head bolts till they bottom out on the heads. Those bolts will hold the gaskets in place and they won't move around while your scribing around the intake ports.. Once you get all the scribing done on the heads, it's time to do the intake manifold.. With the gaskets still bolted down on the heads, use a little "2B" Permatex blue sealer on the intake side of the gaskets.. A very thin layer is all you need.. First brush some blue ink around the intake ports of your favorite intake manifold and let dry. While thats going on, carefully remove the Allen head bolts from the cylinder heads without disturbing the gasket positions.. The gently lay your intake in place and start screwing in the intake bolts you plan to use for the engine build. Tighten those down no more than 15-18 foot lbs. Next, let motor sit for about an hour and go have lunch or something. After about an hour or so, start removing the intake bolts carefully and lift the intake manifold straight up. Flip the intake upside down and set it on your bench. You'll notice that the intake gaskets are now glued in place ready to do some scribing. Once you get the scribing done on all the ports. gently lift the gaskets out of the way so you could re-use those for the final buildup or use a new set of the same brand of gaskets. Unbolt the cylinder heads from your block. Now you have a matched set of heads and intake manifold that you can blend together the ports on. Man, I hope this all made sense.. Good luck and don't go hog crazy!!!
To make a long story short, I made my own shoulder bolts by grinding the shoulders .050" long and the diameter of the mounting holes in the gaskets..
My street formula: Gasket match intake side, blend into bowl area. Clean out casting flash in bowl area on both Intake and Exhaust, smooth Exhaust port walls. Keep out of short turn area, and get a valve job from a reputable shop. Less is more, keep it simple. I've done a few this way with good results. If I were racing, I'd let the professionals do it. When it comes to changing the shape or volume of the port, you really should know what you're doing and have the right tools. A man has to know his limitations.
For porting at home, an electric die grinder can be your best freind... It's not that loud as a neumatic version. Sears Craftsman has one and so does Makita which is more expensive. Wear a good quality face mask and safety glasses/face shield when doing this type of work.
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