[Tom Vaught]

Ok time to talk about the last Picture in my previous post.

I learned something today.

Here, in the previous post, we have a 6 pack set-up (Tri-Power) on a Weiand "Rat Roaster" intake manifold.

The bare Weiand manifold looks pictures #1, #2, #3 below and there is a drawing from MOPAR Performance on how to fix the poor cylinder to cylinder distribution to the runners when the system is run only off of the center carb.

Lots of effort in trying to get that idle fuel to the runner inlets but difficult because the plenum is flat and not very tall.

So then we go back to post #269.
Here the gentleman mounted up a rat roaster intake on his engine but he did something different. HE IS RUNNING THE ENGINE NORMALLY OFF THE END CARBS. Just like a Pontiac Dual Quad intake would be running off the primaries on a pair of AFBs. So the air fuel mixture is right over the front pairs of runners and the mixture is right over the pairs of rear runners. Straight shot right to the ports cruising down the road.

So then the gentleman needs more cfm so he opens up a 625 cfm 2-barrel in the spot where a normal primary carb would be. That carb is just adding more cfm to the overall plenum at high speeds. So all of the issues the MOPAR guys had with the intake can be fixed by how you think about running the Primary Carbs and the Secondary Carb.

If you look at his linkage you will see that he is opening up the 350 cfm carbs at the same time and then the linkage opens up the Large 625 CFM center carb later on.

Picture #4 shows all of the mods required to the lower intake plenum to get the fuel distribution even close at low rpm and normal cruise speeds.

Tom V.