i have recently purchased a new set of 062 heads for my next engine... and have been looking at getting some more exhaust flow as they are little better than any other SBC head on the exhaust side...

i had been wondering if complete remove of the valve guide protrusion into the port and blending would be a significant gain... enough to justify the grinding or in my case 3 minutes a piece with the bridgeport or would it be a total waste of time?

pics to better illustrate what i mean

 

You do not need to or want to completely remove the exhaust valve guide boss.
The guide boss supports the valve as it opens and closes.
You can get all the flow you need by slimming, streamlining and shortening the valve guide boss some. Using a die grinder and carbide bit carve two paths around the guide boss on either side. You'll be widening the port *slightly* at that point and slimming the diameter of the guide boss.

With proper porting your 062's exhaust ports can flow well over 200cfm.

by the way, your pictures are of a intake port.
the suggestion in the pic of maintaining a constant cross sectional area in the port is all wrong for an exhaust port. The exhaust is leaving the port under high pressure and heat (its expanding).

it's not nessessary to completely remove the guide boss in an intake port to get it to flow either.
Give the guide boss a streamlined shape, shorten it a bit and widen the port/bowl roof at the boss to give the airflow, *direction* around the valve guide boss.
The 062 heads are pretty good as cast so don't get too carried away.

 

Pick up the book "Max performance for Small Block Chevy" written by David Vizzard. They are available at Autozone or Books a million. Very good detail on how to port heads. BTW he (and everyone else I've heard) does not recommend removing the guide bosses. Although I have read about this modification in 5.0 Ford books.

 

i under stand it is an intake port... couldnt find a very detailed exhaust port

but it was my understanding that the larger bowl area would allow more flow into the port

 

True, but your valve will rattle around with no support, and probably get too hot as well.

 

how much do you think i should leave around the valve maybe .035 on either side with a height around .350-.400? think that might be enough to stabilize the valve? then i could open up around the boss a bit? looking for ideas for serious improvements no matter how much work is involved... i have the time

 

You can take down the height a bit, but not much. .035" is way too little. Press in guides have about a .065" wall for the thick walled bronze ones, you'd want more then that. I'd say 1/8" min.

 

Like F-Bird'88 said, the correct procedure is to streamline it and turn it into a sort of airfoil shape, rather like an airplane wing, NOT to simply eliminate it.

No matter what you do, you can't eliminate the valve stem; amd if you were to simply lop the guide off, you'd create a HUGE discontinuity where the stem meets the port.

I use a diamond bit with a "ball" shape in the roof around guides; it makes a smooth, uniform path for the material to flow through. Imagine taking a garden hose and shooting water into the bowl, and I think you'll figure out right away what you REALLY need to be doing. A bunch of typical shadetree "hogging out" will basically just ruin a good set of heads.