my 5.1 engine had a rocker that was not moving. Also popping through carb with a rich mixture. Would the fact of the rod being bent just by a slight 1/16 of an inch enough to cause a problem?

 

Rocker not moving indicates a problem. Push rod being bent normally means valve was in the way and piston moved it. Some more teardown is in order unless a other engine is planned.

 

Would my best option be to take the car to a person who rebuilds them ? They offered to rebuild it for 3,000. or just the top end for 1500. Does this sound right? Or should I take off the spring an the valve stem would this give me any info?

 

The money seems right but will likely go up. You never know what you have till you get it apart. Hopefully the tech your working with knows about the HT4100 and has the tools to work on it if he has to remove the heads. Piston and cylinder are replaceable in kit form, if necessary. Your problem could relate to a worn out camshaft which is not uncommon.