Maybe too easy....but possibly a small header leak?
I have a leak in the #4 cyl. (back passenger), but it makes a heavy "TCK" noise progressing to a sound similar to a bad pulley. At first you could only hear it under load conditions similar to what you described, but it progressed to being audible at idle over time.
I'm going to swap that gasket when I install my intake week after next.
Who knows...maybe?
--nathan
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--silver_pilate
'91 GT, Built 306, Wolverine 1087 cam, ported Windsor Jr. Irons, and all the goodies...click the link to the left to see a full list of my mods...
Tried and True 302 Being Built to Outrun You! heh heh heh...
--Texas Panhandle--
Check out my site
[This message has been edited by silver_pilate (edited 10-02-2001).]