Help w/heads question

[gs97chevys10]

I have #882 400 heads and noticed the cross flow from center exhaust ports. what is this for and can it be blocked like say from victor high rise manifold look alike. ?? thanks Gary

[Scotty_S-15]

Do you mean the exhaust cross-over that flows across the intake? If so, All stock heads have this. It was part of a system to enhance cold weather & cold engine performance.

......... All early V8s had a butterfly valve below one exhaust manifold with a bimetal spring that would shut or minimize exhaust flow when cold and no load. That would force some exhaust to cross over through a passage in the intake, warming the intake charge and the carb. On some intakes, it also provides exhaust for the EGR valve.

........... Can you block it? sure. Most Hi-Perf manifolds don't have this passage, as with most Hi-Perf heads. I think some intake gaskets can be had with a Stainless Steel insert there to block the passage when using stock type heads and intake. Long time ago I put some thin SS shim stock under an intake gasket to do the same, took the intake off a few months later, burned right through. http://www.s10v8.com/images/smilies/icon_mad.gif http://www.s10v8.com/images/smilies/icon_razz.gif

[gs97chevys10]

weeew couldnt remember if it could be blocked or not, thought soo, but didnt want to mess up. My 1205 felpro doesnt have the hole of course and thought i messed up and got wrong heads.wont be using these heads for long but for now they will do the job. hey thanks scott<<? i appreciate it . Gary