Unshrouding - was Heron Pistons and Larger Valves

[Swann, Benjamin R. (BSWANN)]

I'm all ears on this, as I am still contemplating tearing a perfectly good
head apart to achieve supposedly minimal gains.  This is on an 87.5 GT motor
272 cam recipient in to 4KQ with Stebro exhaust.

I would be happy to know that this is really more trouble than it is worth.

Ben
Project GTQ on the backburner.

<
On Mon, 18 Dec 2000 16:17:35 -0700, "Bruce Bell" <bbell04 at attglobal.net>
wrote:

 > [ ... ]
 > If you are going through this much trouble use the pistons from
 > an 85 or 86 GTI/GLI and  bore the block to 81.5 mm. This should
 > yield you a 10:1 CR. which you can lower by unshrouding the
 > valves while cleaning up the combustion chamber.

I'm curious about what is meant by "unshrouding" the valves in
the context of head work. I've come across this term before
where there can be a shrouding effect due to the close proximity of
the valve to the cylinder wall which then acts as an impediment
to flow. But this seems different. Please fill me in. Thanks,

>