Val 360
I had the same problem with my freshly built engine. And by the sounds of it the same specs. First time I started it it wasn't there. We did a tune and then decided to scrap the old carb and distributor. Second time around the same knock as yours began.
It turned out that three of the pulley bolts that sit around the crank bolt were gone. This was due to a couple of things I did wrong. 1. No lock tight on those bolts 2. I cheated and used a impact wrench on those bolts instead of hand tightening them 3. The engine mount bolts needed to be tighter. I had about a inch lift on it when we discovered the problem. Now that those bolts are back in and TIGHT there is no knock.
See how it goes, I'd bee interested to see if this helps.
Cheers.
