Besides color and about 20 bucks in price what are the diffs in the Golden Knight series and the standard engines?

Most, if not all, have a velocity stack on the carb.

That is about it,but they look like they have a better finish and oohh they look so nice sitting out in the open.It also solves the should I cowl the motor in or not with it looking so purty you will want to leave it open.

I think the GK series are worth the extra money. It isn't but $14 more if you add the cost of a velocity stack. I have one on my .72 and also on a NIB .82. The stacks help prevent fuel from spitting out of the carbs. All carbs mist or spit, but most is not visible. My .72 began spitting larger drops and I put it on.