I have a 66 diesel that I had restored; when it ran before the restoration I was told it was very hard to start. In fact they would use almost a whole can of starting fluid in the summer to get it going. The hard starting happened after they had the vavles ground; my mechanic told me that you DO NOT grind vavles in the diesel engines. I would suggest you do a compresion test on your cylinders; after all it is compression that makes your engine work. I also put an electric pump on my 66 and it works great; you only need to be able to dump the fuel back to tank when the engine is not running and the pump is.