4age bigport head: port & polish

[BenR]

Yes i know, but the majority of the basic work is quite easy and clear for all to see.

Just get a stock head and you can see the problems.

Leave the stock seats unless you can find someone who actually knows what to do regarding cutting valve seats properly. I've just spent £50,000 on a cnc valve seat machine for this very purpose.

In the pics you can see the stock head, and how you clean up the bowls, this is the only area you need to concentrate on, forget about the whole port, just the bowls.

Tidy it up with carbide burrs, then just smooth it with some 80 grit 1" wide emry clotch on a slotted shaft, be careful of the seats at all times.

You can also see what is needed to be done on the short sides and how far from 'round' they are and how they do not point in the same direction due to the ports offset.