Knock Knock, what's there?

[Tony & Kim Zager <beagle@idir.net>]

Hello, all.

My 69 Spitfire (with a 1500 engine) is making a loud knocking sound.  It only 
happens after the engine is warm, and only around 2500-3000 RPM, whether 
under a load or not.  Rod bearings or water pump? Any ideas?  I guess I'll find 
out 
for sure when I tear the sucker apart, but any insight would be appreciated.

Thanks,

Tony Zager
1969 Spitfire Mk 3