| Oh, ok I see what you've got there. It is not ideal that the bowl area before the seat ring has a big scoop out of it. Nor that the port opening is so damn huge. I have seen this on Ducars. The ports have been ruined by the factory. Basically they have not left you anything to work with. There are three options open to you if you want to persist with this head.
The first is ignore the problems and do the best you can to clean up without enlarging.
The second is to install a larger seat and valve. That way you will reclaim some workable material and be able to rectify the bowl area and be able to shape the port to a preferred shape. This will mean though following up with a big bore kit and cam and bigger carby to make the whole thing work. This is exactly what is done with the big hp motors. It is the best option as far as power goes, just know that it is a very committed path in money and time.
Or number three, you can use a filler to reduce the oversize areas and shape to your liking. This way you can improve the flow and stick with stock valving and carb if you want to. The easiest way to do this is with JB weld. All you have to do is clean the port surface up like you have already done. Then drill with a tiny drill a few holding holes into the areas you want to fill being carefull you have meat behind those spots. Then gouge the entire surface to be JB welded with your alu cutter. It is then just a matter of mixing it up and building it up all through the areas you want. It can then be sanded to any shape you want.  |