my little 4.8 is gonna be gettin a cam soon and the lifters are tapping so the heads will be coming off. what all can be done to the factory heads as far as machining? milling, port and polish (is that helpful?). anything else? im not plannin on spendin a lot of money just something good to get done while its all apart

 

Find a reputable machine shop, have them cleaned up and and fresh valve job. No porting unless they know how to really port, and have the flow capabilities to back it up.

Some machine shops are 'pros' that can only hamper you output, when done incorrectly.

 

have them milled about .015 and a 5 angle valve job! after they are milled have them unshroud the valves

 

what the fluck is unshroud the valves??

 

Machining or grinding the area that supports the valve stem in the intake or exhaust port.
You have to be carefull when doing this, too much material coming off will cause a valve guide to weaken or be unsupported and may cause other issues like a vale sticking, becoming cocked or something worse!!
This is done basically to increase flow or reduce turbulance in the intake or exhaust.
I have never doen this but have seen heads that were done, and a few that were over done by amatures that got a little exuberant when unshrouding.

 

Actually, unshrouding the valves consists of grinding a small portion of the combustion chamber adjacent to the intake and exhaust valves, to eliminate a step that impeads flow around the valves. Pocket porting involves removing/shaping the valve guides in the port bowl. Bowl porting and unshouding the valves (in a scientific method) accomplishes approx. 80-85% of total porting gains in most cylinder heads. If you do this in an un scientific way, you can actually decrease flow of a cylinder head. Porting cylinder heads is not something that is learned by looking at pictures, and reading books. (though that is a VERY important "step" in learning head porting) A die grinder and LOTS of time turning ***** on a flow bench is where it's at. A good understanding of aerodynamics also helps. Look at the way water moves around a spoon held into the sink faucet stream, and you can learn a thing or two about air movement. Then spent time at the airport on a foggy day watching air move over a wing on a jet. You need to be able to "see" air moving in your head as you grind a port. With the cost of cylinder heads for GenIII stuff so cheap, buy a die grinder and have a go at it. If you slow down, buy another set and have another go at it. Sooner or later you will accomplish something worth while. If you don't have the patience for it, pay the money for a pro to do it for you. It takes me approx. 14-18 hours of porting for a race set of heads, and I have been doing this for over 25 years.