[Jakno]

I have a 35 Pickup with a rebuild 1937 59A engine. Has approx 1K miles on it since rebuilt. The noise is more of a rapping or tapping sound and it's seems to be located in the lower right front of the engine. I have had several mechanic's say it's not a bearing noise. Maybe a wrist pin or piston slap ?.
Good oil pressure and truck starts and runs well.
Have taken the fan belt off to eliminate the water pumps and have tried finding anything listening with a screwdriver on engine .
The noise started out real faint but now has progressed to fairly loud at half throttle under light load.

If you have any thoughts or experience, I'd be grateful. I'm hoping to get a better idea before I pull the engine and start hunting. Thanks.