Finally, someone mentioned "Valves". I agree with most here, that this motor needs a complete go-over, including an over bore. The intake pop has nothing to do with the block, heads yes!!!. Were the valves lapped and the valve stems checked for wear? Were the "J" heads cut for the 2.02's done correctly (they look like two valves may touch. I spent over $4,000.00 on a complete rebuild on my 340, 35 years ago and it was money well spent. Note: A motor should be built for its use. In my case, I built a tight clearance block for long use, where a loose block clearance would be for a race app. There are so many variables, including oversized carburetion, cams, torque converter, rear gearing and tire size, that should be considered in an engine rebuild.
