I do all my own head porting. I also port all my own carburated intakes. I extrude hone the EFI intakes because you cannot beat the smooth airflow this process produces. I totally agree with everyone that Extrude Hone charges a fortune for their work, but look at the world speed records they own with this process. It is not just a few cars. It is in the 100's of cars now.
I have my trick flows ported to the 1262 felpro gasket, and my only caution for you is that your B cam is TOO SMALL to take advantage of these huge ports. The 1262 gasket is only a 1/4 inch shorter and wider than the 428 cobra jet heads that made over 600 hp on my engine.
If you port them this far, go up to the E cam or even the X cam.
I like guys who port themselves. I love doing it. Pull all the valves. When you do, take a small fine file and remove the grove along the valve keeper ridge of your valves, then they will drop right through the guides. Clean the port bowl of all the gubbers, but do not go hog wild here. Just a basic clean up.
Like others have said, you only need to blend the port match back about 1/2 inch into the port. I like to widen the port floor to about 80% the valve diameter, but you run the risk of hitting a water jacket and then you have an expensive paperweight.
So you can go about 75% without a problem just go slow and error on the side of safety. The top side OR "port roof" is where you need things really smooth and really well blended. Put all your time here and you will reap some big dividends.
I forgot which heads you are running. If they are Ford iron heads you need to completely remove the air injection bump. Port the exhaust the same as the intake with the emphasis on the port roof. Make sure you size up your header to the gasket, because if you go too wide and tall you might compromise the header seal and this will cost you big time. BIG TIME.
If you have aftermarket heads they probably have decent runners on the exhaust side, but clean them up anyway, and make sure all the gubbers are removed from the port bowl. I like to use the flapper rolls to highly polish the exhaust port after I have everything roughed out. But if you run in a stock class, this type of exhaust porting will put you in a modified class.
So take your ported head to a shop and have it shot peened to put a cast finish back on the ports. Tech may still complain and you may end up in a modified class anyway if they know their heads....
Hope this helps and I am really glad you want to do this yourself. I ported my first heads at 16, but I had a great teacher who did world class head porting work. He taught me that big is not necessarily better.
Enlarged and smooth exhaust ports, and smooth intake runs are what works best on low rpm street and bracket engines.
Only high high rpm engines take major reworking in order to keep the air and fuel suspended as they navigate at extreme velocity past port floors, bowls, valves and valve guides, and the like. On an 8,000 rpm engine the air and fuel will separate as they make sharp bends or hit port sides etc. This can cause really disastrous engine problems.
Feel free to email me at
jim_howard_pdx@yahoo.com if you have any questions. Porting is fun, it is highly effective, and it is ADDICTIVE.
Good luck and don't hesitate to email me with ANY questions.