302 upgrades...

[67coupe]

You need a 1/4" die grinder with a good deburing bit, some different shaped grinding stones and small flapper sanding wheels. They also offer an attatchment that I don't know the proper name of, but it is multi layers of abrasive and you keep peeling it down as it dulls.

The trick is if you hit the wrong spot near the valve seats you can ruin a head. You have to remove the valves first. The intake runners are good enough for street use. The exaust are very poor. Take a header gasket and bolt it to the head. Paint around the inside of the port so it shows how far is to far to go. On your heads there is probably a cast hump where air injection would have been if you had an air pump. You can completely remove that and shape that corner like the gasket. The other thing to try and do is make the floor flat as you can and remove some of the arc so it's a straighter shot to the valve. When that is done take the stones and blend all the sharp edges inside the runner and valve pocket. The smoother the better. I put a few layers of masking tape around the edge of the valve seat to protect them from harm. After that shine it all up on the exhaust side with the flapper wheels. Clean it good and take the heads to have the valves done. If you have rail guided rockers I would think about installing guide plates and the early style rockers. I lost one engine because of those rockers, won't ever build another with them in it. Might want to ask the machine shop what it would cost you to go up to 1.94/1.50 valves also. Stock are 1.74/1.45 I believe.

Hope this helps.

[duplox]

The multi layer bits you mentioned are called sandpaper rolls. Its just sandpaper thats been rolled up and glued together to make a tight cylinder. The layers wear away as you go. You can get a kit which consists of a bunch of different grit and size sandpaper rolls, and also some flap wheels from a company by the name of Standard Abrasives. Summit sells it... They also sell their own generic kit, which doesnt include the flap wheels, but its much cheaper(i think the SA kit is 40 bucks and the summit is 20). I got the summit one and bought the flap wheels for my dremel.