Stagger jetting question

66Valiant528 said

Here it is. I hope it's visible. I also got what David Vizard wrote.
And yes, I have a spacer under my 950. Maybe they put it there to even out the fuel distribution as Indy headed smallblock pointed out. Maybe I shouldn't mess with it.

View attachment 1715802218

Click to expand...

That’s what I was alluding to about the firing order. Unfortunately it is more complicated than that. It’s not just the firing order that causes distribution issues. If you have an overall rich condition, or if you have a manifold that isn’t conducive to keeping the fuel in the air and the fuel and air are separating when that fuel hits the floor or even the walls we don’t have any idea where it will go. I remember some stuff on the dyno at one time. The guy doing the port work went to great lengths to get the floor of the manifold into an inverted V shape. I think it was a Victor intake. It was on the dyno for several days and they had numbers for the intake before he did the floor modifications. Once he changed the floor the power dropped like a rock, the BSFC numbers went way up and the distribution was way worse and it didn’t make any sense. I’ll never forget that because the guy doing the work couldn’t understand why the distribution went out of control. In the end, he made the floor flat again and power came back and the BSFC numbers were back in line. The point is many things conspire together to affect or change distribution patterns. You have to be very careful modifying intakes and such because the results aren’t always intuitive.