Agreed, but if you don't want to do that and you use a spacer, I would go open but I'm not sure 1 inch is enoughYa, the stock intake was not made for the bigger carbs. Even with the spacer, you have the sharp edge of the stock manifold that screws up the airflow. A possible fix is to pull the intake manifold & grind a radius to open up the throttle blade area to accept the larger throttle blades if you want to stay with the stock intake manifold. A used dual plane aluminum manifold is a good option.
Never used it but should work
Remove and have it machined to spec. Cheapest route and it'll be just fine. Usually about $60 which is way cheaper than $300+. If you do machine it, take the carb with it.Ya, the stock intake was not made for the bigger carbs. Even with the spacer, you have the sharp edge of the stock manifold that screws up the airflow. A possible fix is to pull the intake manifold & grind a radius to open up the throttle blade area to accept the larger throttle blades if you want to stay with the stock intake manifold. A used dual plane aluminum manifold is a good option.
Thought I was all ready to fit the new AFB 9000 but it transpires the secondary ports are larger than on my inlet so they won't open.
Which plenum spacer should I get? Fully open cut out or with the the two correct size holes? I reckon I can squeeze in an inch high.
View attachment 445542
Agree with 451mopar type of insulator but a 4 hole.I use the thick heat insulator style carb gasket with hardware kit.
Example (0.320" thick): https://www.summitracing.com/parts/edl-9265/overview/